Given the following data from group 1 and group 2:
a. Combine the two datasets in ranked order. Compute the sum of the ranks for group 1, R1. Compute the sum of the ranks for group 2, R2.
b. Compute the U score for each group, U1 and U2, and determine the U_ statistic.
c. Use the Mann–Whitney U statistic to test the null hypothesis that the average is the same for both groups versus the alternative, that the group 1 average is greater than that for group 2. Use a = 0.05.