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PSY 2010 F15 HA 07 Name ___________________________________________________ A psychologist compared three drugs for improvement of memory in the elderly. Three groups of patients aged 70 or older were given either Drug A or Drug B or Drug C. They were then given a task involving memorization of a list of words. The dependent variable in the study was the number of trials to a criterion of a perfect recitation of a list. The data are below. The data of each group are presented in a row, rather than a column to save paper. Obviously, for a between-subjects analysis such as this, the data of a variable will be entered in a vertical column in the computer. Group A 7 10 20 28 12 7 8 10 8 7 35 28 27 26 18 32 45 7 9 10 Group B 7 5 10 11 14 13 18 19 22 17 7 9 10 11 32 10 16 14 13 17 Group C 21 24 28 32 19 23 27 30 26 25 24 29 30 31 39 40 15 38 26 36 Perform the appropriate analysis and complete the Answer Sheet on the next page. In addition, answer the following questions . . . . Extra Questions – showing that the F can be fairly easily computed by hand . . . 9. What is the value of the variance of the sample means times 20? (Hint – enter the means into SPSS or Excel and compute the variance. Then multiply by 20.) 10. What is the mean of the three sample variances? (Hint – square the standard deviations and compute the average of those values.) 11. What is the ratio of answer to 9 / answer to 10? How does it compare to the F statistic printed by SPSS? Hypothesis Testing Answer sheet. H07 Name _________________________________________ 1. Give the name and the formula of the test statistic that will be employed to test the null hypothesis. 2. Do the data meet the assumptions of the test? Provide evidence. 3. The null and alternative hypotheses. Null Hypothesis:________________________________________________________________ Alternative Hypothesis:__________________________________________________________________ 4. What significance level will you use to separate "likely" value from "unlikely" values of the test statistic? Significance Level = ___________________________________________________________ 5. What is the value of the test statistic computed from your data and the p-value? Test statistic value = _________________________ 6. What is your conclusion? p-value = _____________________ Do you reject or not reject the null hypothesis? 7. What are the upper and lower limits of a 95% confidence interval appropriate for the problem? If a Confidence interval is not appropriate for this problem, say so. Lower Limit = _________________________ Upper Limit = _______________________ 8. State the implications of your conclusion for the problem you were asked to solve. That is, relate your statistical conclusion to the problem. Include mention of Post Hoc test results, if appropriate. 9.______________________________________________________________________________ 10._____________________________________________________________________________ 11. ____________________________________________________________________________