Analgesics. A pharmaceutical company tested three formulations of a pain relief medicine for migraine headache sufferers. For the experiment, 27 volunteers were selected and 9 were randomly assigned to one of three drug formulations. The subjects were instructed to take the drug during their next migraine headache episode and to report their pain on a scale of 1 = no pain to 10 = extreme pain, 30 minutes after taking the drug.

Drug Pain Drug Pain Drug Pain A 4 B 6 C 6 A 5 B 8 C 7 A 4 B 4 C 6 A 3 B 5 C 6 A 2 B 4 C 7 A 4 B 6 C 5 A 3 B 5 C 6 A 4 B 8 C 5 A 4 B 6 C 5

a) Use the Kruskal-Wallis test to judge whether there is a difference among the analgesics.

b) What aspect of these data may make the Kruskal-Wallis test more appropriate for these data than the ANOVA methods of Chapter 25?