Use the data sets from problems 2 and 3, on profit as a percent of sales for building materials firms and for aerospace firms.

a. Find the median profit for each industry group and compare them.

b. Combine the two data sets into a single column of profit percentages next to a column indicating industry group.

c. Sort the profit percentages, carrying along the industry group information. List the ranks in a third column, averaging appropriately when there are ties.

d. List the overall ranks for each industry group.

e. Find the average rank for each industry group; also find the difference between these average ranks (subtracting the smaller from the larger).

f. Find the appropriate standard error for this difference in average rank.

g. Find the test statistic for the nonparametric test for two unpaired samples.

h. What is your conclusion from this test regarding profits in these two industry groups?