Refer to Problem 19. Use the technology of your choice to do the following.

a. Apply the paired Wilcoxon signed-rank test to decide, at the 5% significance level, whether the data provide sufficient evidence to conclude that, on average, the weekly earnings of male full-time wage and salary workers exceed those of women.

b. Compare your result in part

(a) to that in Problem 19(a).

c. Obtain a histogram, boxplot, and stem-and-leaf diagram of the paired differences.

d. Based on your results in part (c), is your procedure in part

(a) justified? Explain your answer.