Research on eating disorders. Refer to The American Statistician(May 2001) study of female...

Research on eating disorders. Refer to The American Statistician(May 2001) study of female students who suffer from bulimia, presented in Exercise. Recall that each student completed a questionnaire from which a “fear of negative evaluation” (FNE) score was produced. (The higher the score, the greater is the fear of negative evaluation.) Suppose the FNE scores of bulimic students have a distribution with mean μ = 18 and standard deviation σ = 5. Now, consider a random sample of 45 female students with bulimia.

a. What is the probability that the sample mean FNE score is greater than 17.5?

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b. What is the probability that the sample mean FNE score is between 18 and 18.5? c. What is the probability that the sample mean FNE score is less than 18.5?

Research on eating disorders. Data from a psychology experiment were reported and analyzed in The American Statistician (May 2001). Two samples of female students participated in the experiment. One sample consisted of 11 students known to suffer from the eating disorder bulimia; the other sample consisted of 14 students with normal eating habits. Each student completed a questionnaire from which a “fear of negative evaluation” (FNE) score was produced. (The higher the score, the greater was the fear of negative evaluation.) The data are saved in the BULIMIA file and displayed in the following table:

Based on Randles, R. H. “On neutral responses (zeros) in the sign test and ties in the Wilcoxon–Mann–Whitney test.” The American Statistician, Vol. 55, No. 2, May 2001 (Figure).

a. Construct a dot plot or stem-and-leaf display for the FNE scores of all 25 female students.

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b. Highlight the bulimic students on the graph you made in part a. Does it appear that bulimics tend to have a greater fear of negative evaluation? Explain.

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c. Why is it important to attach a measure of reliability to the inference made in part b?