252grass4 061 11 14 06 Open this document in Page Layout view Name Class days and time Please include this on what you hand in Graded Assignment 4 The data set is based on problem 11 52 in the 10 th edition or 11 66 of 9th edition of the text It gives the amount of dirt removed according to the cycle time blocked by the detergent used You must answer questions a c for versions A B and C of the problem To enable statistical functions enter Excel and use the Tools pull down menu Select Add Ins and check the two Analysis Tool Pack items If you do not have at least the first of these available on your home computer you may have to use the school computers This year s data is below Row 1 2 3 4 5 6 7 8 18m 0 12 0 10 0 13 0 11 0 09 0 10 0 12 0 14 20m 0 13 0 13 0 14 0 15 0 16 0 13 0 12 0 13 22m 0 17 0 19 0 17 0 18 0 18 0 17 0 16 0 17 24m 0 17 0 18 0 19 0 17 0 20 0 16 0 15 0 17 Note that Rows 1 and 2 are data for Detergent A Rows 3 and 4 are data for Detergent B etc Only neat and legible papers with written answers in complete sentences will be read a At a 5 level is there evidence of a difference in the average amount of dirt removed by cycles of different length Why b What assumptions are necessary in a c What cycle lengths should be recommended Do this problem in Excel as follows Use columns A B C E and F on the Excel spreadsheet for data In the first row of Columns B C D and F put in 18m 20m 22m and 24m Label Column E with 24ma and Column A with brand Starting in Cell A2 Put in the letters A through D to identify the detergents unless of course you want to suggest some names Now put in the data in columns B C D and F skipping column E Version A One way ANOVA To fill column E in cell E2 write F2 After your enter this cell should read 0 17 Highlight cell E2 and use the fill handle on cell E2 to make column E identical to column F except for the heading Do not go on unless this is true Save your data as wdataA xls Use 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 E 9 Select New worksheet ply and columns check labels in first row hit OK and save your results as wrslA xls Version B Two way ANOVA In order to check for the effect of the fact that the data is blocked by detergent repeat the analysis using ANOVA Two Factor with replication Set input range to A 1 E 9 check labels if it s there and save your results as gresltB xls Put 2 in rows per sample Citing the F s or p values answer questions a c and question d is there a significant difference between the amount of dirt removed by the detergents and does the use of the detergents as a factor change your conclusion about wash cycles Cite p values and or F values Version C Take the last digit of your student number if it s zero use 10 and divide it by 100 Call this y and make sure that I know its value For example Seymour Butz s student number is 101321 so he uses y 01 Go back to your original data or use the file pull down menu to open wdataA xls To fill column E this time in cell E2 write F2 y where y is the number you just figured out Now highlight cell E2 and use the fill handle to make column E equal to column F minus y Do not go on unless this is true Relabel Column E as 24mc Save your data as wdataC xls Run the one way ANOVA again and save your results as wrsltC xls Submit 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 ANOVA do a Scheffe confidence interval and a Tukey Kramer interval or procedure for the mean of the best cycle length versus the other 3 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 2 Take the data from your last ANOVA and perform a Levene test on it using the third example in 252mvarex as a pattern for your calculations using Minitab Make sure that you explain what is being tested and what you conclude To do this copy your data into columns 1 5 If you did 1 and have your numbers in c1 and your column names in c2 you can unstack the data by using MTB Unstack c1 SUBC Subscripts c2 SUBC After SUBC VarNames But you will have to move it around afterwards You can do a lot by using the data pull down menu and clicking on copy and letting it prompt you on what move you want Remember that your column labels should be written in above the columns Put row labels in column1 Just to make sure that you are in the right place print out your data and run a one way ANOVA using print c1 c5 AOVO c2 c5 The test is simply vartest c2 c5 unstacked Don t give me results without explaining them Extra Extra Credit Do Bartlett and Levene tests by hand using the examples in 252mvar as your pattern It turns out that your ANOVA has just enough columns to do this test 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 logarithms of variances Label Columns 10 12 stdev var and log Use the data that you already have in four columns in Minitab c2 c5 labels in c1 and get the variances as follows name k2 stdv1 name k3 stdv2 name k4 stdv3 name k5 stdv4 stdev c2 k2 stdev c3 k3 stdev c4 k4 stdev c5 k5 print k2 k5 stack k2 k5 c10 let …
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