Refer to the Journal of Accounting Education (Vol. 25, 2007) study on homework assistance for accounting students, Exercise 8.18. Recall that students were randomly assigned different levels of assistance on the homework. Some (20 students) were given the completed solution, some (25 students) were given check figures at various steps of the solution, and the rest (30 students) were given no help. After finishing the homework, the students were all given a test on the subject and the knowledge gains (improvement in test scores) determined. The accompanying table gives the sample median knowledge gains for the three groups of students.

a. The researchers theorized that as the level of homework assistance increases, the test score improvement will decrease. Do the sample medians reported in the table support this theory?
b. What is the problem with using only the sample medians to make inferences about the population median knowledge gains for the three groups of students?
c. The researchers conducted the Wilcoxon rank sum test to compare the median knowledge gain of students in the "no solutions" group with the median knowledge gain of students in the "check figures" group. Based on the theory, part a, set up the null and alternative hypotheses for the test.
d. The observed significance level of the nonparametric test of part c was reported as .456. Using a = .05, interpret this result?

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Check Figures No Solutions Completed Solutions Sample Size Sample Median 25 2 30 3 20 2