Lab report Essay Example for Free

Lab report EssayA molecular(a) public exposure experiment of propanone-air (redundant w/ last sentence. . concise)was conducted with the goal of determining the spreading coefficient of acetone into air. For this experiment, acetone was placed in a outpouring tub 3mm OD, 2mm ID . . (is that correct? ) NMR tube? e and was every last(predicate)owed to diffuse into non-diff employ air that was passed over the footrace tube. The air that passed over the tube was from natural circulation in the way of life and no air was forced over the top of the test tube.The dispersion occurred over a period of somewhat eight hours, with readings taken each hour. After analyzing the info collected from the per fashionance of this experiment, tThe airing coefficient was calculated to be 0. 098 + 0. 02 cm2/s at T = ?. After completing our calculations, oOur results were then compared using the Chapman-Enskog comparability as rise as the Fuller, Schettler, and Giddings method. The diffu sion coefficient calculated by the Chapman-Enskog was 0. 990 + 0. 001 cm2/s and the result of the Fuller, Schettler, and Giddings method was 0.104 + . 002 cm2/s. The books value found in Perrys Chemical Engineers Handbook was 0. 125 + 0. 00 cm2/s. (at T = ?. . . or extrapolated from? ) The agreement of our method with the other methods available for calculating the diffusion coefficient was very good (how good is very good. .. signifi give the axet discrepencies or not? ), and also agreed well with the literature value found. This conduct to a conclusion that this method of determining the diffusion coefficient of acetone into air can be aconsidered a reasonably reliable method. BACKGROUNDMolecular diffusion is the transfer or movement of individual molecules through a fluid by random molecular movements (Geankoplis 412, year of publication). In the diffusion process, the molecules of interest current from regions of high concentration to low concentration. Molecular diffusion can occur in both directions with the system. In the case of the diffusion tube experiment, however, acetone diffuses through non-diffusing air, which is passed over the top of the test tube containing the acetone. The air is all toldowed into the test tube, but does not diffuse into the acetone.Molecular diffusion of gases has been studied for many years. Molecular diffusion is a mass transport process Motivation for its study comes from the fact that chemical separation processes such as distillation, drying, ion exchange systems as well as many other processes dep wind up on molecular diffusion (Kirk-Othmer Vol 8, p 149(check format)). EXPERIMENTAL METHODS For the performance of this experiment, a junior-grade test tube was filled approximately a third full of acetoneBe specific. . how small, starting height, diam, etc.This test tube was then vertically placed in a 10mL graduated cylinder which contained small beads. The purpose of the beads was to look that the test tube rema ined vertical. This assembly was then placed on a digital scale. The amount of air movement provided by the ventilation system was assumed to be adequate so as to ensure that the concentration of the acetone at the top of the tube was zero. An initial acetone level in the test tube was taken, as well as the mass of the assembly and the temperature of the subject surrounding the assembly.After this initial data was taken, the area temperature and mass of the assembly were taken approximately every hour for the following eight hours. The final level of the acetone in the test tube was taken when the final temperature and mass reading were taken. DISCUSSION OF RESULTS From the data collected from the experiment, the diffusion coefficient was calculated using equation 6. 2-26 from Geankoplis (Equation 1) As the z value was only preserve at the beginning and the end of the experiment, the intermediate values of z had to be calculated.The following equation was used for the calculation of the intermediate z values (Equation 2) Thus, all values but DAB were known and could be plotted versus time to obtain a linear plot. By rearranging equation 1, it can be seen that the list of this plot will be equal to 1/ DAB (Equation 1. 1) The initial plot of data which includes all invests is shown below in Figure 1. This plot contains all records and has an R2 value of 0. 9478. From this plot the molecular diffusivity coefficient was determined to be 0. 108 + 0. 022 cm2/s. Figure 1 First plot of data in Equation 1The second point in the data (t=2700s) showed no diffusion occurred in the first 45 minutes, which seems unlikely (yes, good- sensitivity of balance, etc). If this point is taken as erroneous, the R2 value goes up to 0. 9639 (more substantial here will be the confidence interval on the slop. . . get that from Tools- Data Analyis-Regression menu in Excel or else in Polymath or TableCureve, etc) and the molecular diffusivity calculates out to be 0. 098 + 0. 021 c m2/s. The plot of the experimental data excluding the second point is presented below in Figure 2.Figure 2 Second plot of data in Equation 1. . forcing through zero point is good. . . looks to me like first FOUR points would give a lower Dab then the last 4. Problems with next 3 that lie below line? Anytihing suspicious happening here? To determine the time it takes for the system to reach steady state, the following equation can be used to calculate the fraction of steady state the system is at (Equation 3) By plotting the value of ((NA)t/(NA)t=? ) versus time, the curve in Figure 3 was generated which demonstrates the systems come near to steady state. Wow, great Cite source.(still wonder about SST conditions of 1st 4 pts though. . . Figure 3 Fraction of steady state versus time From this plot, it could be give tongue to that the system achieves steady state in 115 minutes however, there is strong evidence this may not be accurate. As mentioned earlier, the second point may be erroneous. This would change the path of the curve. In addition, data was not collected at a high enough frequency for this curve to be highly accurate at predicting the time to steady state. If in fact the second point is erroneous, the system could energise come to steady state well before 115 minutes.This time of 115 minutes at best, could be the upper bound (or lower bound according to Whitakers criteria in his bind (handout). . . not sure for the time it takes for the system to come to steady state. The scatter in the data can be attributed to various factors in the experiment. The scatter could be attributed to the changes in temperature, as the temperature did fluctuate slightly through the duration of the experiment Good. At what time did it stabilize?. The change in temperature would cause a change in the partial pressure of the acetone leading to further deviations.In addition, there was no measure of airflow past the tube. Changes in the airflow could also have contri buted to the scatter as it could effect the concentration of the acetone at the top of the test tube (Good ). The diffusion coefficient was also calculated using the Chapman Enskog equation, (Equation 4) and the Fuller, Schettler and Giddings method. (Equation 5) A literature value was also found for acetone at K(check Perrys), which was corrected to our experimental temperature using the correlation (Equation 6)The values obtained with these methods as well as those from the experimental data are presented in Table 2. Table 1 Values of molecular diffusivity coefficients found. ** ** A very good way to show this graphically in Excel would be to use a bar graph showing the values of Dab as height of a bar by method used, and error bars to easily demonstrate any overlap of uncertainty, discrepancy, etc. Example The Chapman Enskog method is accurate within 8% and the Fuller Schettler and Giddings value has a lower accuracy than the Chapman Enskog (Geankoplis 425).The Chapman Enskog va lue is less than 1% different than the experimental value and the Fuller Schettler and Giddings value only about 6% different. From this analysis, it seems these equations predicted the experimental value very well. These calculated values are about 20% lower than the literature value. This variance may come from the inconsistent temperature in the room or from pressure fluctuations in the room caused perhaps by the starting and stopping of the HVAC systems. For the derivation of Equation 1, several assumptions are make. Beginning with the general equation (Geankoplis 6.2-14) (Equation 7) One assumption was that because the case examined was a diffusing A (acetone) into non-diffusing B (air), the diffusion flux of air into the acetone (NB) was equal to zero. Another assumption made was that since the total pressure was low, the acetone gas diffusing into air was an ideal gas. This allowed for the term c to be replaced with its ideal gas equivalent, P/RT. Additionally, the air extre mely over the test tube was assumed to contain no water vapor. An average air velocity that was uniform was passing over the acetone containing test tube was also assumed.There are non-idealities that exist in the molecular diffusion of acetone into air. Some of these non-idealities are corrected for in the journal from downwind and Wilke. Acetone displays surface tension effects which, instead of having a perfectly horizontal liquid surface, give the liquid acetone a slightly downwards curved liquid level. Because of this curvature, the actual diffusion path length that the acetone travels is smaller than what the diffusion length would appear to be based on join liquid level or calculated liquid volume (Lee 2384).Along with a non ideal liquid surface, the air passing over the open end of the tube may cause some upheaval to exist in the top portion of the tube. With its existence, the turbulent area of the tube will cause a length to exist inside the tube where the concentration of acetone is zero. With the presence of this acetone vapor-free region, the diffusion length is again shorter than it would appear to be. To account for the non-idealities in the diffusion process, Lee and Wilke do not use the apparent diffusion path. Instead, they use an good average diffusion path which they give by(Equation 8) Where x is the effective average diffusion path, ? xs is the length of the curvature of the non-ideal liquid to account for the surface tension forces, ? xe is the length of the tube where the acetone vapor-free region exists due to turbulence that exists from the passage of the air, and ? x is the sum of ? xs and ? xe (Lee 2384). When this is substituted back into the diffusion equation, it becomes the following (Equation 9) Where Da is the apparent diffusion coefficient and D is the true diffusion coefficient based on the true diffusion path (Lee 2384).The way our experiment was setup, the driving force for the air across the test tube was natural air flow and did not employ forced air flow. Because of this, the length of the tube where the turbulence existed in the Lee and Wilke journal would most likely not have been present in our experiment. Also, the initial liquid acetone level selected in our experiment was such that the length of the curvature due to the surface tension forces on the acetone would have been negligible when compared to the apparent diffusion length of the tube.The initial height of the liquid in the tube for this experiment was chosen wisely. The reason for this is that with the initial level that was chosen, a sufficiently long diffusion path existed such that the non-idealities that were accounted for in the Lee and Wilke journal entry would have had a very insignificant impact on the results of our experiment. CONCLUSIONS AND RECOMMENDATIONS From the data collected an analyzed, it has been determined that the experimental procedure used here can determine the molecular diffusivity coefficient with some level of accuracy.For future experiments, some form of air flow regulation should be investigated. Something as simple as a room fan could be placed next to the scale to ensure a more constant air flow. Another increase in accuracy could be achieved by regulating the temperature with more consistency. If the experiment could be performed in a large insulated room, the temperature may not vary as much. Good job on Discussion, Conclusions, etc. . . to improve maybe expand to relate what YOU mean are the main uncertaintys that caused problems in your particular case and show evidence to support.

Writing Locations posted on course website Essay Example for Free

Writing Locations posted on course website EssayImportant punctuate Anyone who is not able to write the exam on the scheduled date must provide documentation validating his/her absence, i.e. doctors note confirmative illness and inability to write exam dated the day of the exam. Once documentation is received and approved by your professor, the value of your midterm will be added to your final exam. If valid documentation is not provided, the midterm mark will be a zero.20 Multiple Choice questions15 Short serve up questions, 2 to 6 marks each(80 marks total)TOPICS TO BE COVEREDThe relationship between the firm and its external environment Critical success factors what they are, why they are important, how they connect to each other Diamond-E model key variables, connections among variables, principal logic, examplesExternal analysiswhat it is, how to conduct one, general vs. specific environments, benefits and repugns of conducting one PEST factors elements, carry on on bu siness, questions to answer from PEST analysis Porters five forces model explanation of each forces impact on pains profitability, methods of reducing the impact of each force, strategic questions it answers, industry examplesEntrepreneurshipwhat it is, what the key elements are, its significanceentrepreneurial process elements, influences, and connection with Diamond-E components of opportunity recognitionhow to screen and evaluate opportunities for viability and agonistic advantage high versus low potential ventureshow to access resources, bootstrapping, pros and cons of financing options social entrepreneurship what it is, key facets, stakeholders, how it compares to traditional entrepreneurship, how it compares to charity, examplesTechnological Factorsopportunities and threats of technology technology standard wars description, impact, scopeinstalled base, lock-in, chemise costs, complementary goods, network effects description, importance, example key assets and strategies to win technology standards warssustaining technologies what they offer, who they serve, examples disruptive technologies what they offer, who they serve, examples, why disruptive innovations can cause large firms to fail, how different types of innovations challenge existing firmstactics for small companies to succeed and for large companies to avoid failureCiting sources and APA Formatting-objectives, rules, methodologyRelevant Readings/MaterialsPearson Textbook Chapters 1,2Lab ManualTechnology Readings (directions for accessing on pg. 199)Introduction to Writing and Using SourcesHow to Use SourcesAPA Documentation StyleAPA In-text Citation FormatPearson resources on citing and using APA formatCases are not covered on the exam.SUGGESTED STUDY APPROACHFor each outcome identify questions that may appear on the exam. These questions can fall into four general categories 1. What is it, what are the general elements of the topic2. Why is it important, why are the individual element s important 3. How are the individual elements related to each other? How are they related to the topic? How does the topic or its elements relate to the topics? 4. Provide an example to help explain your answers and/or illustrate the elements and topics.YOU CAN DO IT GOOD LUCK

Dana Hall Essay Example for Free

Dana Hall EssayDevelop an action plan, taking into consideration the organizational context and current understanding of the issues. In this assignment, you argon asked to stretch your thinking a bit, by designing a preliminary action plan based on your analysis of the Dana Hall case. Instructions 1. canvass the action research you have completed thus far on the Dana Hall case. 2. Design a preliminary action plan for addressing the issue at Dana Hall.Use the Action Research Template (in the Resources below) to guide the development of your action plan. Your plan should o Emphasize the problem definition stage (Stage 1 of the ARPP), including the propagation of alternative courses of action. o Align with the problem definition. o Include analysis of the Dana Hall situation and the organizational context of the problem. o Establish alternatives and your choice for a course of action. 3. Present you analysis of the problem and your preliminary action plan. Choose one of the follo wing two options.

Aal Mir: Analysis of Fairtrade Policies

Aal Mir Analysis of Fair change over PoliciesAbstractAal Mir is mavin of the leading java producers in the UAE. The unions tack and logistics capabilities have proven to be exemplary for other companies. Aal Mir is one of those companies which have been undis endowed for more than 30 historic period. Its uninfected tack policies attract a spectacular number of customers towards it. The union has lead to acceptance of chocolate as one of the primary snack in the area. The products produced by the fraternity are quite favorite in the region and it acts as a good source of income for the smart set. The nation of UAE usually prefer products prepared within their uncouth more than the products produced outside which serves to the service of the accompany and earns higher profit to the company. The company is very strict against child toil which reflects in its fair trade policies.The delineate prepared is a pass on of in depth analysis of the companys policies which are quite oriented towards fair trade of the company. The company has also played an consequenceant role in increase sentiency about some cordial causes. The project deals with analyzing the business of the company and its role in creating favorable awareness amongst the masses.The company is strictly against child labor and low final payment of the employees which has resulted in a great increase in the goodwill of the company. The company has also been involved in meetings with the world health system of rules which is an indicator of the extent of social responsibility of the company. The various aspects of the policies of Aal Mir have been covered in the report.Children between the age of 10-15 years serve as the major erupt of the target population for the company and the company lays emphasis on children even in its fair trade policies.The affinity of the local population of UAE towards goods produced within the country also acts as a positive point for the company an d works to the advantage of the company as has been seen in its year of establishment. The consumption of chocolate in the region has increased in the region by a growth rate of more than 10% annually over the last few years as a result of companys products and its policies. In fact the consumption of camel milk and biscuits has also gone up significantly over the last few years. The report has also emphasized on these growth factors as a result of the policies followed by the company since its establishment.IntroductionThe term fair trade is referred to the concept of social justice along with continuing the business trades of a company in coiffe to gain maximum profit from it. It was originally used in order to support social justice. In the concept of fair trade justice was defined as the strongest thought that arises through simple majority among people. The main(prenominal) engender of fair trade is to identify the relationship between various aspects of international trade identifying the reasons for putting constrained on the traded products. The objective of fair trade is to husband the people in the region and the employees of the company from being exploited by the companies in order to maximize their lettuce.Aal Mir has been chosen as the company to study its fair trade policies because it has been operating business in UAE for the last thirty years and has not been a smash of any controversy or dispute since it came into existence. The company has also shown good growth rate since its establishment in 1980 becoming the largest producer of chocolate in the country. The companys strategies and policies are a great combination which has conduct to higher net profit and has also earned social goodwill for the company. The company has always served its social duties along with earning one of the highest pay in its area of trade and business. The company has been strictly against some of the social evils such as child labor and low wages of emp loyees.Body of ReportChocolate is the product chosen to study the fair trade policies of a company. Chocolate today has been selected as a fair trade product by fair trade organizations (Fair trade product). The organization chosen to study the fair trade policies is Aal Mir.Background of the companyAal Mir trading company was constituted in Dubai in the year 1980 by devil dynamic entrepreneurs who worked in partnership to make the company reach heights of success. The company was setup by Mr. Mir Motalleb Vakhshouri and Mr. Mohd. Hassan Baba Hassan and its business today is spread in alter fields and different areas of the food market (Aalmir overview).Initially the company began with business focusing on the confectionery segment and then shifted to modern trade and distri saveion by and by analyzing the trend of the market and started importing food and non-food items to Dubai (Aalmir overview). forthwith Aal Mir Trading Co. LLC has a very impressive portfolio which consists of various strike outs that have been recognized internationally and enjoys the status of a leader in full fledged distri stillion in the region. Its logistics and marketing strategies have been appreciated over time and its marketing covers many areas of the market. (Aalmir overview)The company does import and export of all kinds of confectioneries, foods and beverages to countries like Iran, Iraq, Qatar, Kuwait, Oman ,India, Pakistan and some African countries. (Spread of Aal Mirs Business).The raw materials required for preparing chocolates are cocoa, oils and fats, improvers and adders, flavors and cereals. hot chocolate serves as the main ingredient for the preparation of chocolate. The main producers of Cocoa are West African countries such as Ivory Coast and Ghana and the company also imports Cocoa from these countries which serve as a main raw material for the production of chocolate. (Areas where Cocoa is produced).The range of product sold by the company consists of bis cuits, wafers, cakes, chewing gum, candies and toffees, foodstuffs like oil, coffee, sift etc, gift boxes, jellies, juice and drinks, lollipops, marshland mallows, pickles and canned food, toiletries and cleaning products and snacks. Such a wide range of products marketed by the company not only reduces the rescue factor but also has led to higher levels of income for the company and has led to independence of the company from any one product for its profit (Products produced by Aal Mir).Aal Mir is amongst the top trading companies and owns many subsidiaries either part or totally in order to smoothen its work. Some of the subsidiaries owned by Aal Mir are Sweet Garden General Trading Co LLC, Aal Mir storing Co. LLC, Tania package LLC, Hassani and Aal Mir Trading Co., Aal Mir Partners Trading Company and Shamim Trading Co. LLC. ( buster Companies)Sweet Garden General Trading Co is an independent company which executes the groups strategy of enhancing its market coverage. This s ubsidiary was established in the year 1989 and is currently working as an independent distribution company. The company is located in Dubai. (Associate Companies)Aal Mir Storing Co LLC in the first place provides storing and logistics services to the companies agreed with it and the company is mainly a holding of Aal Mir Trading Company and is presently functioning in Dubai. (Associate Companies)Tania is a label brand of Aal Mir Trading Company for its food products like rice and grocery items. Apart from being a label company the company also gives support services such as repackaging. The company s hardened in Dubai (Associate Companies)Hassani Aal Mir Trading Co. is another associate of Aal Mir trading company situated in Abu Dhabi. This company works operates its business in the field of consumer products and branded confectionary. The company does its work with the support of companies like Sweet Garden General Trading Co. LLC and Aal Mir Trading Co. LLC and is situated in Abu Dhabi the capital of UAE. (Associate Companies)Al Mir Partners Trading Co. LLC is another associate of Aal Mir Trading Co. LLC that has been operating within the Sultanate of Oman and trades and distributes foodstuffs and confectionaries in the region of Oman. (Associate Companies)The trading of Basmati rice in the region is done by the company under the established brand name Shamim which is a brand established by the company. (Associate Companies)Fair Trade Policies of Aal Mir Trading Co. LLCFair trade policies not only benefit the people associated with the company and the common people of the country but also benefit the company by increasing the goodwill of the company. Fair trade policies aim at benefitting the people of the country who whitethorn be associated with the company as producers of raw materials, consumers or employees of the company. These policies result in creating goodwill for the company and also sometimes attract big number of customers to the products of the company. These policies create a thought in the minds of the customers that the company that is performing the deeds for social causes and that is has a high probability to be keep the rights of its customers carry on and will not exploit or harm them and it also creates a sense of belongingness to the organization in the minds of the minds of the consumers.The company is strictly against child labor and has a view that children are not meant to be exploited for gaining profits. This can also be seen as a marketing strategy as the main market of the company is children below 15 years of age and by being strict on child labor the company wants to give a put across to its customers that it really cares for them and is willing to do any possible attempt to stop any kind of evil done on them.Moreover on part of being a chocolate company it is important to take care of the hygiene and the conditions in which the product is manufactured as unhygienic products could lead to drear y health and also lead to loss of customers and reputation to the company.The companys fair trade policies are also quite visible by its attempts to increase the frequent awareness about all its products to the consumers it also tells the consumers the value that they hold great importance for the company and facilitates them with a feeling that they are the most precious source of gross for the company. This form _or_ system of government attracts a large number of consumers towards the company and makes them interested in buying the products of the company.The company is a firm believer of globalization and is taking any possible step to implement it. This shows companies respect for international trade and its respect for personnel internationally thus helping itself to grow globally. The global presence of the company is felt by analyzing the countries to which the company currently exports its products. This policy helps the company in building international goodwill of the company.The company is also against giving low wages to its employees and is a firm believer that a person should be paid for whatever he does for the company thus giving the employees a sense of proceeding and motivates the employees to work with dedication for the company and company as the employees feel that the company belongs to them and any benefit to the company would lead to the personal benefit of the employee.Aal Mir Trading Co. is one of those few companies which have been able to remain undisputed over the span of more than 30 years which reflects its fair trade policies.The company has pioneered in getting rid of various social issues of the world and has been praised for its stairs taken worldwide. The companys meetings with the world health organization act as a firm confirmation to the steps taken by the company in order to reduce social evils and exploitation of labor worldwide.AppendicesOpposition to child labor.Maintenance of Hygienic conditions during product ion.Attempts to Increase general awareness among the consumers.Respect for international trade and personnel.Opposition of low wages.Results of Policies implemented by Aal Mir Trading CompanyAs a result of the fair trade policies implemented by the company there are various figures that support its success. In the last few years the annual growth rate of chocolate consumption in the region has been around 10% which directly reflects the increase in profit of the company as it is the leading producer of chocolates in the region.Today more than 25% of the people in the region consider chocolate as a main snack which is far greater than the ratio of 2.5% which existed 15 years ago.The results are even visible in the biscuit industry which is one of the areas of business of the company has witnessed a growth of around 17% in the last few years.Is the company adapting to fair trade policies only as a marketing tool?The main motive behind any company is to earn maximum possible profit wit hin the laws of the region in which they operate. The motive of Aal Mir Trading Co. is also to earn maximum profit from its business but the policies implemented by the company in order to gain this profit are quite noble and are based on social welfare. Although seeing from a point of view we may find that these policies are helping the company to gain higher profits but seeing the level at which the company is performing it is not a necessity for the company to work for social causes as the people already are aware of the brand and the products produced by the company. In its thirty years of working the company has been able to make a good reputation in the market and has made good profits over the last few years. In the initial stages of the working of the company it could be made out the company baron have gained larger profits based on the basis of the policies that it had implemented and in the initial stages this could have been seen as a policy to take the people of the re gion into confidence but since the company is in existence for over 30 years the company today does not need to take the consumers into confidence as the company already has enough customers that are confident about the working of the company and have faith in the products of the company but at this stage the steps might be interpreted as a measure to maintain the goodwill of the company and keep the people assured of the policies of the company. Another important fact that must(prenominal) be kept in mind while analyzing this aspect is that in order to follow such fair trade policies the company still has to put in extra cost which might just go wasted as the company already has a huge customer base and activities of social good now has a minimal effect in increasing the customer base of the company. Hence on analyzing the trade policies it is found that although the company may be earning a higher profit based on response of users on these policies but the credit of doing such ac tivities must not be taken away from the company that is putting an effort for the community as the company is fulfilling its social requirements hence we can say that Aal Mirs adaptation to fair trade policies is not just a marketing policy but it is an attempt by the company to improve the society which in turn is giving higher profits to the company.ConclusionAfter going through the policies of the company and the profits that it is earning and also after examining the impact of these policies on the company as well as the people of the region various conclusions can be made out which have been stated in this paragraph. The company has developed into a leading producer of chocolates as a result of its trade policies and has also earned the stature of an extremely ethical company that fulfills its social responsibilities. This sense of responsibility of the company towards the society is a result of the companys fair trade policies. The companys contributions have also been highly recognized by the society and even bigger organizations like the world health organization. The company has earned its spot at the top and is expected to stay there as the companys policies as well as quality and cost of products are cut back to attract a large number of consumers towards the company. Hence it can be concluded from the above report that the good policies of the company that includes the fare trade policy have helped the company to establish a customer base and then its products and marketing strategies have helped it to affix the companys position at the top amongst all the companies of the region thus resulting in the current scenario where the company is at the top of the market and is still developing its position.Works CitedAalmir overview. (n.d.). Retrieved 5 4, 2010, from http//www.aalmir.com/AboutUs.aspx?id=1Areas where Cocoa is produced. (n.d.). Retrieved 5 4, 2010, from http//www.zawya.com/story.cfm/sidZAWYA20090203034717/UAE%20chocolate%20makers%20see%20 red%20as%20cocoa%20prices%20soarAssociate Companies. (n.d.). Retrieved 5 5, 2010, from http//www.aalmir.com/AboutUs.aspx?id=3Fair trade definition. (n.d.). Retrieved 5 4, 2010, from http//www.fairtradecoffee.org/articles/ft-definition.shtmlFair trade product. (n.d.). Retrieved 5 4, 2010, from http//www.globalexchange.org/campaigns/fairtrade/cocoa/Products produced by Aal Mir . (n.d.). Retrieved 5 4, 2010, from http//www.aalmir.com/Products.aspx?id=2000Spread of Aal Mirs Business. (n.d.). Retrieved 5 4, 2010, from http//www.made-in-china.com/traderoom/ismaeili

Toyota motor corporation strategy

Toyota motor commode strategyI. Introduction of ToyotaOverview of Toyota Comp bothToyota push back Corporation is one of the leading railway c fitted car manu incidenturers in the world. It is founded in August 28, 1937 in Japan. Akio Toyoda is the current president of Toyota motor company. As of March 31, 2009, the capital of Toyota is estimated as 397.05 one thousand million yen. The major blood undertaken by Toyota is Motor Vehicle Production and Sales. It has been estimated that around 320,808 employees working at present in Toyota and its affiliated companies in tout ensemble over the world as of March 31, 2009 (Toyota, 2009).Even though Toyota was up to(p) to primary(prenominal)tain a steady growth rate both in gross gross revenue and production of vehicles till 2008, because of global economic crisis both the gross revenue and production of vehicles of Toyota has been come down in 2009. The company has seduced 5,100,000 vehicles in Japan itself in 2007 and 5,160,000 in 2008. But the production has come down to 4,255,000 in 2009. On the other hand the company has recorded 23,948.0 million yen sales in 2007 and 26,289.2 million yen in 2008. But the sales engender souse to 20,529.5 million yen in 2009. 8,524,000 Toyota vehicles have been sold in the world in 2007 and 8,913,000 in 2008. But the piece of vehicles sold has slipped to 7,567,000 in 2009 (Toyota, 2009).International, regional, industrial environment of ToyotaToyota Company is currently operating(a) in five continents and in 27 countries with 53 manufacturing units a recrudesce from its main manufacturing units in Japan. It has operations in more than one hundred seventy countries each over the world at present. It always acquires a place in the top 10 Fortune Global 500 enterprises list. It has a in effect(p) reputation as the to the highest degree socially and environmentally responsible automaker in the world (Global Toyota, 2007)Toyota Financial Services (TFS) provides vehicl e financing in 33 countries worldwide. Some of the most diverse and fastest-growing among our global network of offices be those in the Asia Oceania Region. Over the last 5 years, their average annual asset growth has been a staggering 30 percent (Toyota Financial Services Global Presence, 2009).Toyota is operating in one of the highly contested automotive sector. Apart from internationalist railway car becomers like, BMW, GM, etc, Toyota is facing challenges from domestic automobile manufacturers such as Nissan, Mitsubishi, etc. Toyota believes in localising the vehicles in order to cater the specific need of the regions in which it operates. For example, Indian business conditions and American business conditions are entirely different for Toyota and they have specific custom made vehicles for different regions. Toyota has implemented a Just in cartridge cargo holder (JIT) production system which is highly debated in the global corporate sector. (Just in Time, or JIT Toyota s Manufacturing Technique, 2005)International and global strategyA company with multinational branches and degree quarters can be referred as a global pie-eyed. (What is a global firm? n. d) It is not necessary that a company producing goods locally and sells it internationally, necessarily a global firm. A global firm always produces goods locally and internationally and sells it in different market across the world. Moreover, a global firm always look for making custom made goods for international market. For example, it is not possible for vehicle manufacturers to make a standard vehicle suitable for the international market. Even the resembling product needs customization for different market because of the difference in international markets with respect to culture, politics, legal aspects, environment conditions, economic conditions etc.Toyota is operating in more than 170 countries at present with 53 manufacturing units all over the world as mentioned earlier, which is cl early an indication that Toyota is a global firm. Moreover, Toyota is addressing the needs of the diverse customers around the world and they were able to make vehicles suitable for regional preferences. For example, for Indian conditions, Toyota has introduced two vehicles Qualis and Innova which can accommodate more people in the same car whereas such vehicles may not suit for the American conditions. Americans like luxury cars more than the Indians and Toyota concentrated in making luxury cars for American market. Thus, Toyota was able to realize the tastes of local people and they succeeded in producing vehicles suitable for each country which made them a true global company in all senses.II. The international environment1. Toyota-Competitors/RivalsToyota is one of the leading automobile manufacturers in the world. Competitors are struggling to compete with Toyota because of the superior quality, excellent supply chain, and very good later on sales support, Toyota offers to th e consumers. In fact competitors are forming regional blocs to compete with Toyota. General Motors, Volkswagen, Ford, Honda, Fiat, Renault, Nissan, BMW, Hyundai etc are some of the major competitors for Toyota in automobile industry all over the world. DaimlerChrysler and BMW sure GMs invitation to abet in joint development of hybrid technology, in part to gang up on Toyota (Target, Toyota Competitors Try To Trip Up the Carmaker on Its Way to No. 1, n. d.). In other words, the competitors are making all efforts to prevent Toyota from sustaining its superior performances. They have realized that nobody can compete with Toyota singly at present because of the superior technological advances and features incorporate to Toyota vehicles and that also at cheaper rates compared to the competitors.In America, General Motors is the main rivals for Toyota whereas in Europe it is BMW. In Asia the major challenges are coming from Hyundai whereas in the home country, Japan the major compet itor for Toyota is Honda. Toyota is facing challenges not only from the American and European car manufacturers. In fact they are facing challenges from their Asian counterparts, Korean car manufacturers like Hyundai and Kia. These Korean companies are offering vehicles with nearly similar qualities as that of the Toyota vehicles at cheaper rate than the Toyota vehicles. They have advertised their vehicles in comparison with the Toyota vehicles a direct attack on Toyota. In other words, Toyota is targeted from all the corners Asia, America, Europe etc. While the domestics and Germans battle to hold their ground, Korean automakers Hyundai and Kia are attacking Toyota from a second front (Target, Toyota Competitors Try To Trip Up the Carmaker on Its Way to No. 1, n. d.)Toyota company makes a hybrid-powered (gas and electric) sedan the Prius that is being snapped up in US and European markets (Toyota Motor Corporation Toyota, Aichi Japan, 2009). This vehicle from Toyota is more envir onment friendly and fuel efficient and it is also in accordance with the Obamas proposal to rejuvenate the auto industries in America. GM and other European car manufacturers are already afraid of the new initiation from Toyota. They are already on the verge of destruction because of the current global monetary crisis. The new user friendly and environment friendly hi tech car from Toyota is a great challenge for the competitors.Toyota is not stripening blindly against the electric car technologies. They have lot of concerns about the success of electric cars. Mitsubishi Motors started leasing its all-electric vehicle, the i-MiEV, in June. Next year, Nissan Motor is set to release its electric car, the Leaf. But Toyota does not plan to introduce an all-electric car until 2012 (The New York times, 2009). If the experiments of Mitsubishi and Nissan found success, they can lead the car market in future at least for some time. But Toyota is anticipating certain problems in electric c ars and unlike others they are not going all out for the electric cars.In short, Toyota was able to read the automotive market well so far, which helped them to keep the number one spot amidst stiff competitions from all over the regions in the world.2. The market structureIII. The internal environment of the company1. Corporate strategyCooperative arrangementRelationship with suppliersRelationship with suppliers Toyota believes that one of the most important factors which makes a long-term and stable procurement of the best products with the lowest price in the most speedy and timely manner is a ending relationship with suppliers wherever Toyota operates. This relationship, which is called keiretsu in Japanese concept, bases on mutual respect and trust, communal growth and development between the company and suppliers.In order to course a deep relationship with supplier, Toyota ran a program, namely guest engineer program, in which Toyota allows suppliers engineer working in plan t for two or triad years. This plan helps suppliers increase their technological advantage, thus will fully meet the corporations technological standard demand in manufacturers processes. Toyota also often sends engineers, and occasionally old executives, to the suppliers company to study their operation and culture. Through the information which was shared intensively, but selectively, and the understanding, supervising the operations of suppliers in this program, Toyota developed the capabilities of suppliers, which coupled with increasing value for the corporation.Although keiretsu is a time and money consuming process, and sometimes is a risk investment if supplier cannot meet the requirement after finishing the program, it allows suppliers control more in terms of cost, quality and delivering to the market than ever before. Because of that, Toyota believes that it is worth for spending resources in building a deep relationship with supplier.Relationship with sales networksToy ota has made pledge directly with about 300 dealers within Japan and approximately 7,500 overseas dealers. This sales network is considered as the first point for Toyota apply their Customers first policy. The corporation and dealers work together with mutual trust to intensify the customers satisfaction and convey Toyota values, which are emphasized in the superiority of Toyota product and service. In order to chase customers satisfaction, Toyota and dealers engage in activities based on constant and close communication, including various forms of support from Toyota, customers feedback and comment of dealers.The Kaizen Development Support Division was established in January 2006 to cooperate with dealers in improving the operation and enhancing customers satisfaction by supporting activities at dealers at Japan and overseas. The offices main activities areExpanding Toyota Product System improvement activities to sales and distribution.Differentiating Toyota dealers from compe titors through improvements.Enhancing customer satisfaction from the customers perspective by implementing on-site improvements.Fostering human resources with the ability to make improvements and reforms using their own skill.After being established, the division immediately held many activities in Japan and overseas countries to foster the development of industry-leading dealers.DiversificationsBesides concentrating on developing mainly motor, TMC also invested in a number of other industries. Most of the diversified businesss capital is the corporations own fund or joint venture with other companies who know clearly the market. The 2 following are the most intensively invested industries in Toyotas diversificationHousingToyota Motor Corporation entered the house-construction business in 1975. After that, this field of business was not intensively invested because the automobile market still was the biggest target of Toyota. The corporation just supplied some lineup of production, including condominiums, built using its unit building system, steel framework construction order or residential steel framing technique. However, when many earthquakes occurred in Japan in 2003 and others house-construction brand faced to difficulty to meet the requirements of customer, Toyota decided to take part in the market by establishing Toyota Housing Corporation. The corporation was completely invested by own fund of Toyota Corporation with 100 million yen at the establishment, and aimed the purpose that Toyota Housing Corporation will become the number 1 seller detached house in Japan.Financial serviceSince being established in 1983, Toyota Financial Services has developed from a small company with eight associates to one that currently employs approximately 3,000 associates nationwide with managed assets in excess of 65 billion dollars.The Toyota Financial Service brand identity was launched in 1999. It plays a role to market the productions of Toyota Motor Credit Corpor ation (TMCC) and Toyota Motor Insurance Service (TMIS). TMCC was incorporated in California in 1982, started operating in 1983. The productions which the company provides are retail and wholesale financing, retail leasing, vehicle protection plans and certain other financial function to authorized Toyota, Lexus and Scion dealers, Toyota forklift and Hino dealers as well as Toyota Material Handling, U.S.A. dealers, affiliates, and their customers in the United States (excluding Hawaii).Opening the Toyota Financial Service was the right move of the corporation in that time in order to increase total profitability from a new potential market. Toyota Financial Service made profit immediately after establishing, and now it contributed a considerable factor in total Toyotas income, which is 623 million dollars while Toyota loose approximately 5 billion dollar in monetary year 2009 due to financial crisis.2. Human resource commissionThe relationship with employeesThe labor-management re lationship in Toyota was strongly emphasized in 1950, when Kiichiro Toyoda and his executive staff were instinctive to resign with 2,000 other employees after the corporation suffers the sharp reduction of automobile demand. This incident had the strong impact on employees and built an absolute trust on the corporation because it represents the due care and sharing difficulty from the corporation with them. Since then, Toyota has been working to develop mutual understanding between employees and management.The relationship between Toyotas employees and manager is considered as one of the most factors contributing on its success. One concept has being intensively applied for building this relationship among Toyota members is Toyota Way, which is supported by two main pillars Respect for people and Continuous improvement. All employees at any level in Toyota have been required to use these two values in their nonchalant work.Human resource developmentToyota concentrates mainly on de veloping and conveying the Toyota Way between employees based on OJT (on-the-job training) in the human resource management policy. In 2002, the Toyota Institute was established in order to improve implementation of Toyota Way by overseas affiliates. The Institute develops and deploys training programs on the core aspects of the Toyota pigeonholing and also provides management training. Besides, a series of lectures, namely The things I learn from Mr. Ohno and Mr. Suzumura, are held, which base on the desire conveying the Toyota Way properly and accurately of Chairman Fujio Cho. These actions created a strong corporate culture, which has fundamental impact on the performance of the corporation.In 1988, the organizational restructuring was implemented to make the decision-making less vertical. This process was change in 2006 when smaller groups were created to enhance teamwork and work-related skills, and reinforce the work ethic in light of the importance of raising the skills of organizations and groups.In 2006, TMC established RD Learning Centre and run the Pro-WIN education program, which is mechanism allowing individuals accomplish their goals in production and production engineering. The RD Learning Centre aim to reinforce the foundation for development of the production and to maintain and enhance Toyotas high-quality.3. The value chainToyota Motor Corporation is one of the largest companies in the vehicle industry, and has branches in most of the worlds countries. In order to stay warlike, Toyota strives to provide clean and true(p) products, to provide fuel-efficient vehicles and to make use of advanced technology.http//www.toyota.com.au/toyota/events/environment/homeThe inbound logistics of ToyotaToyota forms its culture and principles through continued growth. Therefore the most important step is to produce vehicles in accordance with sound environmental standards. The company continually improves the accuracy and the efficiency of the use of its resources. Toyota produces less than 2 kg of waste per vehicle, and is working to squeeze it to less than 30 kg in the coming years.http//www.toyota.com/about/enviroreport2008/03_recycling.htmlThe operation of ToyotaToyota focuses on supervision in its industrial processes, and this improves the quality of every stage of manufacture and ensures the continual improvement of the companys standards. Visual observation is used to assess the process, and each team member is responsible for his or her work. Moreover, any team member is able to stop the process if any part of it is incorrect.http//www.toyotauk.com/main/how-we-manufacture/Toyotas marketing and salesToyota is one of the largest automobile producers in the world. The company ensures reliable customer service, and consistent sales, by managing over 529 branches around the world. And they are looking forward to improving those sales as well.Toyota servicesToyotas services continue after the sale by ensuring that all of its ve hicles are under warrantee for 3 years or 60,000 km, whichever comes. Any defects in the vehicles during this time are repaired without cost to the owner. Toyota also provides many financial services for the customer, such as vehicle loans that are repaid in monthly installments. Toyota provides additional services, such as being able to repair your car in any of its branches throughout the world. As well as Toyota always contact their costumer on phone or email to ask them about the services and how they let on it.http//www.toyota.com.au/parts-and-serviceVehicles manufactured in Toyotas factories are sent to authorize distributors. And also they have the genuine spare parts so that, they can fix the care in every branch.Outsourcing activitiesIn 1977, Toyota made a deal with Fujitsu, a Hong Kong-based company, where Toyota transferred about 77 employees to Fujitsu for training. Since then, Fujitsu has worked with Toyota to develop new technology and to improve the companys global b usiness performance.Fujitsu is a giant in the field of technology. The partnership allows Toyota to develop new hardware and software as well as provides the ability to sustain a competitive advantage. As a result, the cooperation of Toyota and Fujitsu will enable Toyota to use the latest techniques in automobile production.

Corrections for attenuation and corrections for range restriction

Corrections for fading and disciplines for escape restrictionOne of the most permeant systemological problems in the educational and psychological field entails determination of the techniques which ar to be utilised in assessing the nature and strength of the descent between versatile measures. Of course, the coefficient of correlation coefficient has provided the field with a viable statistical tool for solving this problem. Unfortunately, in some instances the appropriateness of correlational techniques may be limited by the operation of certain statistical biases in actual data bases. Thorndike (1949) has noned that two of these biases, termed range restriction and attenuation effects, curing up exert a healthy diminishing influence on the magnitude of discover correlation coefficients.Range restriction occurs when a investigateer wants to estimate the correlation between two inconsistents (x and y) in a universe, but subjects argon selected on x, and data for y be only available for a selected sample (Raju Brand, 2003). This occurs for example when scores from admission tribulations be used to predict academic success in higher education or are compared with grades in the program they were admitted to (Gulliksen, 1950 Thorndike, 1949). Because infusion is made on the grounding of scores from these kinds of instruments, the range of scores is restricted in the sample. Although the correlation between bear witness scores and academic success can be obtained for the restricted sample, the correlation for the population of applicants remains unknown. Due to the range restriction in shield scores, the correlation obtained is expected to be an underestimate of the correlation in the population (Hunter Schmidt, 1990 Henriksson Wolming, 1998).attenuation effects refer to the fact that an observed correlation coefficient will tend to underestimate the unfeigned magnitude of the relationship between two varyings to the extent that the se measures are non an accurate reflection of true variation, i.e., to the extent that they are unreliable. In some utilize studies, the operation of these biases may be acceptable. Yet when an investigation centers on determining the true strength of the relationship between two sets of measures, the operation of these biases in the experimental data base constitutes a serious, a great deal unavoidable, confound (Crocker Algina, 1986 Worthen, White, yellowish brown, Sudweeks, 1999). psychometry has long been aware of the implications of range restriction and attenuation effects with respect to the inferences drawn by researchers concerning the magnitude of relationships. Consequently, a variety of forms learn been derived which permit the researcher to reform data based estimates of the magnitude of a correlation coefficient for the operation of these influences (Guilford, 1954 Stanley, 1971). The aim of this review is to discuss the importance of correcting for range rest riction and correcting for attenuation in predictive validatedity studies and review two methods to correction for range restriction (Thorndikes incident II and ML estimates obtained from the EM algorithmic ruleic rule) and two methods to correction for attenuation (traditional court and latent variable example flack). Results from research evaluating the use of these methods will also be discussed.Importance of corrections for range restriction and attenuation effectsAs early as the beginning of the last century, Pearson (1903), in developing the Pearson product-moment correlation coefficient, noticed problems callable to range restriction and attenuation and discussed possible solutions. Since then, a heavy(p) number of studies piddle examined the biasing effect of these statistical artifacts (e.g., Alexander, 1988 Dunbar Linn, 1991 Lawley, 1943 Linn, Harnisch, Dunbar, 1981 Schmidt, Hunter, Urry, 1976 Thorndike, 1949 Sackett Yang, 2000). It is evident from literatur e that both range restriction and attenuation can create serious inaccuracies in data-based research, especi solelyy in the fields of employment and educational extract.The need for correcting lustiness coefficients for statistical artifacts is becoming to a greater extent recognized. Validity generalization research has demonstrated that artifacts similar range restriction and attenuation account for large percentages of the variance in distributions of validity coefficients. Although the Society for Industrial and Organizational Psychologys (SIOP) Principles (1987) recommend correcting validity coefficients for both range restriction and cadence undependableness, researchers rarely do so. Ree et al. (1994) discussed the application of range restriction corrections in validation research. They reviewed validity articles published in educational and psychological Measurement, Journal of Applied Psychology, and Personnel Psychology between 1988 and 1992. Ree et al. (1994) concl uded that only 4% of the articles dealing with validation subject fields applied range restriction corrections.Researchers may be reluctant to concur corrections for range restriction and attenuation for several(prenominal) reasons. Seymour (1988) referred to statistical corrections as hydraulic, implying that researchers can achieve a desired firmness by pumping up the corrections. Another reason for reluctance in applying corrections may be because the APA Standards (1974) oralise that correlations should not be doubly turn for attenuation and range restriction. The more current Standards (1985), however, endorse much(prenominal) corrections. A third reason for not using the corrections is that knowledge of unrestricted standard deviations is often lacking (Ree et al., 1994). Finally, researchers may be concerned that in applying corrections to correlation coefficients, they may inadvertently overcorrect.Linn et al. (1981) verbalise that, procedures for correcting correla tions for range restriction are desperately call for in highly selective situations (i.e., where selection ratios are low) (p. 661). They continued, The results also clearly support the conclusion that corrections for range restriction that treat the soothsayer as the sole explicit selection variable are too baseborn. Because of this undercorrection, the resulting estimates still provide a conservative indication of the predictive value of the predictor (p. 661). Linn et al. stated that ignoring range restriction and/or attenuation corrections because they may be too large is overly cautious. They adviseed the routine reporting of both observed and corrected correlations. Both observed and corrected correlations should be reported because there is no significance test for corrected correlations (Ree et al., 1994).Based on the logic and suggestions from literature, there depend to be a number of reasons to correct for restriction of range and attenuation in predictive validity s tudies. These corrections could be used to adjust the observed correlations for biases, and thus yield more accurate results.Correction Methods for Range RestrictionThere are several methods for correcting correlations for range restriction. This review is meant to examine two ascendes to correction for range restriction Thorndikes case II and ML estimates obtained from the EM algorithm. These methods will be described first, and then results from research evaluating their use will be discussed.Thorndikes case IIThorndikes (1949) caseful II is the most commonly used range restriction correction formula in an explicit selection scenario. Explicit selection is a process, based on the predictor x, that restricts the availability of the criterion y. The criterion is only available (measured) for the selected individuals. For example, consider the attendingly straightforward case where there is treat selection on x (e.g., no one with a test score below a specified cutoff on x is sele cted into the organization) (Mendoza, 1993). Thorndikes Case II comparability can be written as followsRxy =where Rxy = the validity corrected for range restriction rxy = the observed validity in the restricted separate and ux = sx/Sx, where sx and Sx are the restricted and unrestricted SDs of x, respectively. Both the restricted and unrestricted SDs of x are available at hand.The use of this formula requires that the unrestricted, or population, variance of x be known. Although often this is known, as in the case of a predictive study where all applicants are tested and test data on all applicants are retained, it is not uncommon to encounter the situation in which test data on applicants who were not selected are discarded and thus are not available to the researcher who later wishes to correct the sample validity coefficient for range restriction (Sackett and Yang, 2000).Issues with Thorndikes case II methodThorndikes Case II is by furthest the most widely used correction meth od. It is appropriate under the condition of direct range restriction (a situation where applicants are selected directly on test scores). Researchers used it and proved its appropriateness. For example, Chernyshenko and Ones (1999) and Wiberg and Sundstrm (2009) showed that this formula produced close estimates of correlation in a population.Although the use of Thorndikes Case II formula is straightforward, this formula imposes some requirements. First, it requires that the unrestricted, or population, variance of x be known. Second, the formula requires that there is no additional range restriction on additional variables. If the organization also imposes an additional cutoff, such as a minimum education requirement, applying the Case II formula produces a biased result. In this example, if education level (z) and test score (x) are known for all applicants, a method for solving the problem exists (Aitken, 1934). Third, the correction formula requires two laying claims that the x -y relationship is linear throughout the range of scores (i.e., the assumption of linearity) and that the misplay term is the same in the restricted sample and in the population (i.e., the assumption of homoscedasticity). note that no normality assumption is required for the formula (Lawley, 1943).Another issue that was found in literature with this method arises when it is applied for indirect restriction of range (a case where the applicants are selected on another variable that is correlated with the test scores) even though it has been shown to underestimate validity coefficients (Hunter Schmidt, 2004, Ch. 5 Hunter et al., 2006 Linn et al., 1981 Schmidt, Hunter, Pearlman, Hirsh, 1985, p. 751).Maximum Likelihood estimates obtained from the Expectation Maximization algorithmUsing this approach, the selection mechanism is viewed as a missing data mechanism, i.e. the selection mechanism is viewed as missing, and the missing values are estimated before estimating the correlation. By viewing it as a picky case of missing data, we can borrow from a rich body of statistical methods for an overview see e.g. Little Rubin (2002), Little (1992) or Schafer whole meal flour (2002). There are three general missing data situations MCAR, MAR and MNAR. Assume X is a variable that is known for all examinees and Y is the variable of interest with missing values for some examinees. MCAR means that the data is absent Completely At Random, i.e. the missing data distribution does not depend on the observed or missing values. In other words, the probability of missingness in data Y is unrelated to X and Y. MAR means that the data is Missing At Random, i.e. the conditional distribution of data being missing given the observed and missing values depends only on the observed values and not on the missing values. In other words, the probability of missingness in data Y is related to X, but not to Y. MNAR means that data is Missing Not At Random. In other words, the probability of missingness on Y is related to the unobserved values of Y (Little Rubin, 2002 Schafer Graham, 2002). If the data is either MCAR or MAR, we can use imputation methods to replace missing data with estimates. In predictive studies, the selection mechanism that is based solely on X, the data is considered to be MAR (Mendoza, 1993). Using this approach, we can use information on some of the other variables to delegate new values. Herzog Rubin (1983) stated that by using imputation one can apply existing epitome tools to any dataset with missing observations and use the same structure and output.There are several different techniques that use imputation to replace missing values. The most commonly applied techniques are mean imputation, hot-deck imputation, cold-deck imputation, regression imputation and multiple imputations (Madow, Olkin, Rubin, 1983 Srndal, Swensson, Wretman, 1992). In general, imputation may cause distortions in the distribution of a study variable or in the relationship between two or more variables. This disadvantage can be diminished when e.g. multiple regression imputation is used (Srndal et al., 1992). For example, Gustafsson Reuterberg (2000) used regression to impute missing values in order to get a more realistic view of the relationship between grades in upper secondary schools in Sweden and the Swedish Scholastic Achievement Test. Note that regression imputation is head wordable to use, because all imputed values fall directly on the regression line, the imputed data lack variableness that would be premise had both X and Y been collected. In other words the correlation would be 1.0 if only computed with imputed values (Little Rubin, 2002). Therefore literature suggest using imputed Maximum Likelihood (ML) estimates for the missing values that are obtained using the Expectation Maximization (EM) algorithm (Dempster, Laird, Rubin, 1977).Maximum likelihood (ML) estimates obtained from the Expectation Maximization (EM) algor ithm is imputed for the criterion variable for examinees who failed the selection test for example (Dempster et al., 1977 Little, 1992). The complete and incomplete cases were used together as the EM algorithm reestimates means, variances and covariances until the process converges. The base of EM missing values is an iterative regression imputation. The final estimated moments are the EM estimates including estimates for the correlation. For an extensive description see SPSS (2002). The idea is that the missing Y values are imputed using the following equationwhere and are the estimates obtained from the final iteration of the EM algorithm. Schaffer and Graham (2002) suggested that using EM imputation is valid when examining missing data.Issues with ML estimates obtained from the EM algorithm methodThis approach is seldom used with range restriction problems, although it has been mentioned as a possibility (Mendoza, 1993). In a more recent study, Mendoza, Bard, Mumford, Ang, (2004 ) concluded that the ML estimates obtained from the EM algorithm procedure produced far more accurate results. Wiberg and Sundstrm (2009) evaluated this approach in an empirical study and their results indicated that ML estimates obtained from the EM algorithm seem to be a genuinely effective method of estimating the population correlation.Since there is not much work in literature examining the appropriateness and effectiveness of this approach, legion(predicate) questions need to be answered when using ML estimates obtained from the EM algorithm for correction for range restriction. Many researches need to evaluate the use of this approach in states that are of special interest include simulations of different population correlations and different selection proportions when using the missing data approach. Regarding the EM imputation approach, one key research question is how many cases can be imputed1at the same time as we obtain a good estimate of the population correlation. Correction Methods for AttenuationIn educational and psychological research, it is well known that measurement unreliability, that is, measurement error, attenuates the statistical relationship between two composites (e.g., Crocker Algina, 1986 Worthen, White, Fan, Sudweeks, 1999). In this review, two approaches for correcting attenuation effects caused by measurement error traditional approach and latent variable imitate approach, will be described and results from research evaluating their use will be discussed.traditional approachIn classical test theory, the issue of attenuation of correlation between two composites caused by measurement unreliability is usually discussed within the context of use of score reliability and validity. More specifically, if there are two measured variables x and y, their correlation is estimated by the Pearson correlation coefficient rxy from a sample. Because the measured variables x and y contain random measurement error, this correlation coef ficient rxy is typically lour than the correlation coefficient between the true scores of the variables Tx and Ty (rTx,Ty) (Fan, 2003). When Spearman first proposed the correction for attenuation, he advocated correcting for both the predictor and the criterion variables for unreliability. His equation,rTx,Ty = ,is known as double correction. The double correction performed on the obtained validity coefficient reveals what the relationship would be between two variables if both were measured with unadulterated reliability. Because measurement error truncates, or reduces, the size of the obtained validity coefficient, the effect of the correction is to elevate the magnitude of the corrected validity coefficient higher up the magnitude of the obtained validity coefficient. The lower the reliability of the predictor and/or criterion variables, the greater will be the elevation of the correction. If both the test and the criterion exhibit very high reliability, the denominator of the equation will be close to unity, thus rTx,Ty .The double correction formula was followed by the single correction formula as researchers began to shift the emphasis from test construction to issues of using tests to predict criteria. As the name implies, the formula involves correcting for unreliability in only one of the two variables. The formula would be either rTx,Ty = (correcting for unreliability in the criterion variable only) or rTx,Ty = (correcting for unreliability in the predictor variable only). The rationale for the single correction of the criterion unreliability was best stated by Guilford (1954)In predicting criterion measures from test scores, one should not make a complete double correction for attenuation. Corrections should be made in the criterion only. On the one hand it is not a fallible criterion that we should aim to predict, including all its errors it is a true criterion or the true voice of the obtained criterion. On the other hand, we should not corre ct for errors in the test, because it is the fallible scores from which we mustiness make predictions. We never know the true scores from which to predict. (p. 401)Although most researchers have adopted Guilfords position on correcting only for criterion unreliability, there have been cases where correcting only for unreliability in the predictor was used. However, these occasions appear to be special cases of double correction, where either the reliability of the criterion was unknown or where the criterion was assumed to be measured with perfect reliability. The former situation was not unusual. We often know more about the reliability of tests than the reliability of criteria. The later situation is more unusual in that variables are rarely assessed with perfect reliability.Issues with traditional approachThe correction for attenuation due to measurement error is one of the earliest applications of true-score theory (Spearman, 1904) and has been the subject of numerous debates, spurring criticisms from its very inception (e.g., Pearson, 1904). Despite this, no real consensus on correction for attenuation has emerged in the literature, and many ambiguities regarding its application remain. One of the early criticisms is corrected validity coefficients greater than one.Although it is theoretically impossible to have a validity coefficient in excess of 1.00, it is empirically possible to compute such a coefficient using Spearman correction formula. For example, if = .65, = .81, and = .49,rTx,Ty = 1.03The value of 1.03 is theoretically impossible because valid variance2would exceed obtained variance (error variance). Psychometricians have offered various explanations for this phenomenon. Before the year ended, Karl Pearson (1904, in his appendix) had declared that any formula that produced correlation coefficients greater than one must have been improperly derived however, no errors were subsequently found in Spearmans formula. This led to debate over both how correction for attenuation could result in a correlation greater than one and whether a procedure that often resulted in a correlation greater than one was valid. Many explanations for correction for attenuations supposed dent have been suggested.Error in estimating reliability. Many statistics used to estimate reliability are known to regularly underestimate reliability (i.e., overestimate the amount of error Johnson, 1944 Osburn, 2000). Whereas this bias is tolerated as being in the preferred direction for some applications (as when a researcher wants to guarantee a minimum reliability), the result of correction for attenuation is inflated if the denominator entered into the equation is less than the accurate value (Winne Belfry, 1982). Other researchers have shown that some reliability estimates can overestimate reliability when transient errors are present however, it has been argued that this effect is probably small in practice (Schmidt Hunter, 1996, 1999).Normal effects o f sampling process. Others, including Spearman (1910), have attempted to explain corrected correlations greater than one as the normal result of sampling error. Worded more explicitly, this asserts that a corrected correlation of 1.03 should fall within the sampling distribution of corrected correlations produced by a population with a true-score correlation less than or equal to one. Despite this, it was some time before researchers first began to examine the sampling distributions of corrected correlations. However, some early studies that have examined the accuracy of correction for attenuation are of note3.Misunderstanding of random error. Thorndike (1907) applied multiple simulated error sets to a single set of true-score values and concluded that the equation for correction for attenuation worked reasonably well. Johnson (1944) extended this study and demonstrated that random errors would occasionally raise the level of observed correlations above the true-score correlation. I n those cases, the equation to correct for attenuation corrects in the wrong direction. Johnsons conclusion that Corrected coefficients greater than one are caused by fluctuations in observed coefficients due to errors of measurement and not by fluctuations caused by errors of sampling, as suggested by Spearman (Johnson, 1944, p. 536). Garside (1958) referenced the various bases of error variance in the coefficients as function fluctuations.Latent variable modeling approachLatent variable approach is considered when a multi agential test is used in the admission of students to various schools. Most often a composite measure related to the total test score or subtests are used in such prediction. The use of a multiple factor latent variable model for the observed variables comprising the test can make more efficient use of the test information.Correctly assessing the predictive validity in traditional selection studies, without latent variables, is a difficult task involving adjustme nts to circumvent the selective nature of the sample to be used for the validation. Latent variable modeling of the components of a test in relation to a criterion variable provides more precise predictor variables, and may include factors which have a small number of measurements. For many ability and aptitude tests it is relevant to postulate a model with both a general factor influencing all components of the test, and specific factors influencing more narrow subsets (Fan, 2003).In confirmatory factor analysis where each latent factor has multiple indicators, measurement errors are explicitly modeled in the process. The relationship between such latent factors can be considered as free from the attenuation caused by the measurement error. For example, TheGMAT exam is a standardized assessment that helps problem schools assess the qualifications of applicants for advanced study in business and management. The GMAT exam measures three areas Verbal, Quantitative Reasoning, and Anal ytical Writing Skills. To illustrate the point, lets look at the verbal exam. The verbal exam measures three related latent variables (Critical Reasoning (), Reading Comprehension (), Grammar and Sentence Structure ()). Each of these variables has many indicators. In such model, is considered to represent the true relationship between the three latent variables (, ,, respectively) that is not attenuated by the measurement error ( to ). This approach for obtaining measurement-error-free relationship between factors is well-known in the area of structural equation modeling but is rarely discussed within the context of measurement reliability and validity.Using this approach, once the interitem correlation is obtained, the population reliability in the form of Cronbachs coefficient alpha4could be obtained. Cronbachs coefficient alpha takes the form = )where k is the number of items within a composite, is the sum of item variances, and is the variance of the composite score. The varianc e of the compositeis precisely the sum of item variances ( ) and the sum of item covariances (2).= + 2.The population intervariable correlation is obtained from the two-factor model in the Figure above based on the following (Jreskog Srbom, 1989) = + where is the population covariance matrix (correlation matrix for our standardized variables), is the matrix of population pattern coefficients, is the population correlation matrix for the two factors, and is the covariance matrix of population residuals for the items.Issues with latent variable modeling approachThis approach for obtaining measurement-error-free correlation coefficients is well known in the area of structural modeling, but it is rarely discussed within the context of measurement reliability and validity. Fan (2003) used this approach to correct for attenuation and showed that this approach provided not only near analogous and unbiased means but also near identical confidence intervals for the sampling distribut ion of the corrected correlation coefficients. It is pointed out, however, that the latent variable modeling approach may be less applicable in research practice due to more difficult data conditions at the item level in research practice. DeShon (1998) stated that latent variable modeling approach provides a mathematically rigorous method for correcting relationships among latent variables for measurement error in the indicators of the latent variables. However, this approach can only use the information provided to correct for attenuation in a relationship. It is not an all-powerful technique that corrects for all sources of measurement error.ConclusionIt has long been recognized that insufficient variability in a sample will restrict the observed magnitude of a Pearson product moment coefficient. Since R. L. Thorndikes days, researchers have been correcting correlation coefficients for attenuation and/or restriction in range. The topic has received considerable attention (Bobko, 1983 Callender Osborn, 1980 Lee, Miller, Graham, 1982 Schmidt Hunter, 1977) and today correlation coefficients are corrected for attenuation and range restriction in a variety of situations. These include test validation, selection, and validity generalization studies (meta-analysis Hedges Olkin, 1985), such as those conducted by Hunter, Schmidt, and Jackson (1982). For example, Pearlman, Schmidt, and Hunter (1980) corrected the mean correlation coefficient in their validity generalization study of suppose proficiency in clerical occupations for predictor and criterion unreliability as well as for range restriction on the predictor.There are several methods that can be used to correct correlations for attenuation and range restriction, and some have been more frequently used than others. For correction for attenuation, the traditional method for correcting for attenuation is the best known and is easy to use. However, in more complex modeling situations it is probably easier to adopt an SEM approach to assessing relationships between variables with measurement errors removed than to try to apply the traditional formula on many relationships simultaneously. Fan (2003) shows that the SEM approach (at least in the CFA context) produces equivalent results to the application of the traditional method. For correction for range restriction, the Thorndike case II method has been shown to produce close estimates of the correlation in a population (Hunter Schmidt, 1990). Wiberg and Sundstrm (2009) show that ML estimates obtained from the EM algorithm approach provides a very good estimate of the correlation in the unrestricted sample as well. However, because the ML estimates obtained from the EM algorithm approach is not commonly used in range restriction studies, the usefulness and accuracy of this method should be further examined.Using an appropriate method for correcting for attenuation and range restriction is most important when conducting predictive validi ty studies of instruments used, for example, for selection to higher education or employment selection. The use of inappropriate methods for statistical artifacts correction or no correction method at all could result in invalid conclusions about test quality. Thus, carefully considering methods for correcting for attenuation and range restriction in correlation studies is an important validity issue. The literature reviewed here clearly suggests that practitioners should apply attenuation and range restriction corrections whenever possible, even if the study does not focus on measurement issues (American Educational Research Association, American Psychological Association, National Council on Measurement in Education, 1999).

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10th March 2005The Verizon EDMA CenterP.O. Box 1915Beltsville, MD 20705-1915To Whom It May ConcernI am writing in honorable mention to international charges posted on my most recent phone bill (Billing date 02/20/05). To explain the situation, I traveled to Manchester, England on January 22, 2005 through February 8, 2005. On January 25, 2005, my wife c aloneed to inquire about international calling plans offered by Verizon. She was informed by a Verizon employee that the calling plan cost $4/month and that would empower her to $.08/minute to England. Based on this fact, we used the calling plan for the rest of the time I was England, assuming we were paying $.08/minute.However, when we received the phone bill, the charges for all calls do through the calling plan were charged at $.30/minute. When I contacted Verizon regarding the difference, I was told that each call had a premium returns termination charge attach to it of $.22/minute. My problem with this situation is that my wife was never informed that a premium service termination charge existed. When she signed up for the plan, a Verizon employee specifically told her that all calls to England would be $.08/minute. She was not given a qualifier stating that there was a possibility the charges may be higher due to a premium service termination. Furthermore, we never received literature explaining the details of the plan. Had we known that charges could have been $.30/minute, we would have used an alternative calling plan with much lower rates. Due to erroneous information, or a lack of important information, given to us by a Verizon employee, we were overcharged $89.