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WCU ECO 252 - ECO 252 Graded Assignment 4

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Graded Assignment 4252grass4-072 10/08/07 (Open this document in 'Page Layout' view!)Name Student Number:Class days and time:Please include this on what you hand in!Graded Assignment 4The data set is part of a problem due to Groebner et. al..14 Testers were sent out to 3 branches of a Mexican fast-food chain (Store 1-3). Though the order of thevisits was random, each tester visited each store once. They rated the restaurant on a number ofcharacteristics and their ratings were totaled and shown. Only neat and legible papers with writtenanswers in complete sentences will be read! Make sure that you have access to a copy of Excel withstatistical functions enabled. To enable statistical functions, enter Excel and use the Tools pull-downmenu. Select Add-Ins and check Analysis Tool Pack and MegaStat. This is available in Anderson. Tester Str 1 Str 2 Str 3 1 830 647 630 2 743 840 786 3 652 747 730 4 885 639 617 5 814 943 632 6 733 916 410 7 770 923 727 8 829 903 726 9 847 760 648 10 878 856 668 11 728 878 670 12 693 990 825 13 807 871 564 14 901 980 719Do this problem in Excel as follows.Use columns A, B, C, D, and E on the Excel spreadsheet for data In the first row of Columns B, C, and D put in Str1, Str2, and Str3. Head column A with the word ‘Tester.’ Starting in Cell A2 Put in the letters 1 through 14 to identify the testers – unless, of course, you want to suggest some names.Now put in the data in columns B, C, and E, skipping column DIf you bring this document into Word, the data can be moved into the Excel worksheet by highlighting the cells you want and copying and pasting.To fill column D in cell D2 write =E2. After your 'enter' this cell should read '630'Use the 'edit' pull-down menu and 'copy' cell D2Use the 'edit' pull-down menu and ‘paste’ in cells E3 through E14 or use handle on lit-up cell. Now column D will be identical to E except for the heading. This can also be done as a simple copy and paste. Save your data as rating1.xlsVersion A – One-way ANOVAUse the 'tools' pull-down menu and pick ‘data analysis.' (If you cannot find this, use Tools and Add-Ins to put in the analysis packs.)Pick 'ANOVA: Single Factor. Set input range to $B$1:$D$15. Select 'New worksheet ply' and ‘columns’, check 'labels in first row' hit 'OK' and save your results as rreslt1.xls. Version B – Two-way ANOVAIn order to check for the effect of the fact that the data is blocked by employees, repeat the analysis using ‘ANOVA: Two-Factor without replication. Set input range to $A$1:$D$14, check ‘labels,’ and save your results as rreslt2.xlsAnswer the following: Is there a significant difference between the store ratings? How is this conclusion affected by blocking by testers? Cite p-values and /or F-testsVersion C – One way ANOVATake the last digit of your student number (if it's zero, use 10). Go back to your original data or use the 'file' pull-down menu to open rating1.xls.To fill column D this time in cell D2 write =E2+x, replacing x with the last digit of your student number.Use the 'edit' pull down menu and 'copy' cell D2Use the 'edit' pull down menu and ‘paste’ in cells D3 through D14. Now column D will be more than the original D by the amount of your value of x. Save your data as rating3.xls. Relabel the column as Str 3yy, where yy is 01 – 10, depending on what you added to the column.Run the one-way ANOVA again and save your results as rreslt3.xlsSubmit the data and results with your Student number. The most effective way to do this is to paste the results into a Word document and then add neat hand or typed notes. Indicate what hypotheses were tested, what the p-value was and whether, using the p-value, you would reject the null if (i) the significance level was 5% and (ii) the significance level was 10%, explaining why. You will have two answers for each of your two problems.For your Version C do a Scheffe confidence interval and a Tukey-Kramer interval or procedure for each of the 332C possible differences between means and report which are different at the 5% level according to each of the 2 methods. Extra Credit: 1) Show that you learned something from computer problem 2 by doing part B on Minitab. There should be very little difference in your result.The easiest way to do this is to copy the first five columns from the original Excel spreadsheet. Enter Minitab and use ‘editor’ to enable commands. Highlight the column labels and cells 1-14 of the first five columns. Remember that your column labels should be written in above the columns (Put row labels in column 1). Just to make sure that you are in the right place. Try the following Minitab commands.print c1-c4AOVO c2-c4;Tukey 5;Fisher 5.You should get results equivalent to your first ANOVA but with individual and Tukey intervals done for you.To set up for a 2-way ANOVA stack your data in columns 11 and 12. Stack c2 c3 c4 c11;Subscripts c12 ;UseNames.To move the row labels, copy the labels from column 1 to column 13. Label column 11-13 ‘Rating,’ ‘Store’and ‘Tester1.’ Every number should now have a correct row label. Use the table commands from computerassignment 2 to check your data. I combined the ANOVA, and the table of means command by using the following.Twoway c11 c13 c12;Means c13 c12. 2) Take the data from your last ANOVA. Use the instructions in 1) above to copy it into the Minitab spreadsheet and perform Levene and Bartlett tests on it using the third example in 252mvarex as a patternfor your calculations using Minitab. Make sure that you explain what is being tested and what you conclude. There are two ways to do this. If you want to do it on the unstacked data use the following.Vartest c2-c4;Unstacked.To do the tests on the stacked data use the following. Save and layout your graphs.Vartest c11 c12.You should also test the columns for Normality. The Lilliefors test for column 2 would be the following.NormTest c2;KSTest.Now answer the following. What requirements must your individual columns meet for ANOVA to be valid? What evidence do you have that these requirements were met?Extra Extra Credit: Do Bartlett and Levene tests ‘by hand’ using the examples in 252mvar as your pattern. This is an awful lot of work unless you cheat and use the computer. If you cover your tracks, I’ll never know. To do the Bartlett test you need


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