Refer to the Reading in a Foreign Language (Apr. 2004) experiment to improve the Japanese reading comprehension levels of University of Hawaii students, presented in Exercise. Recall that 14 students participated in a 10-week extensive reading program in a second-semester Japanese course. The number of books read by each student and the student's course grade are repeated in the accompanying table and saved in the JAPANESE file. Consider a comparison of the distributions of number of books read by students who earn an "A" grade and those who earn a "B" or "C" grade.

Number of Books Course Grade

53.................. A

42.................. A

40 .................. A

40.................. B

39.................. A

34.................. A

34.................. A

30.................. A

28.................. B

24 .................. A

22.................. C

21.................. B

20 .................. B

16.................. B

a. Rank all 14 observations from smallest to largest, and assign ranks from 1 to 14.

b. Sum the ranks of the observations for students with an "A" grade.

c. Sum the ranks of the observations for students with either a "B" or "C" grade.

d. Compute the Wilcoxon rank sum statistic.

e. Carry out a nonparametric test (at a = .10) to com pare the distribution of the number of books read by the two populations of students.