15.19 Telephone holding times In Exercise 15.8, the telephone holding times for Muzak and classical music were Muzak 0, 1, 4, 6, 3 Classical 13, 9, 8, 15, 7

a. For comparing these two groups with the Wilcoxon test, report the ranks and the mean rank for each group.

b. Two groups of size 5 each have 252 possible allocations of rankings. For a two-sided test of H0: identical distributions with these data, explain why the P-value is 2>252 = 0.008. Interpret the P-value.