] A drug company tested three formulations of a pain relief medicine for migraine headache sufferers. 27 volunteers were selected and 9 were randomly assigned to one of three drugs. The subjects were instructed to take the drug during their next migraine headache episode and to report their pain on a scale of 1 to 10 (10 being most pain).http://vassarstats.net/ (one-way ANOVA)

• Drug A 3 4 5 4 3 6 4 3 4
• Drug B 5 7 4 5 4 6 5 8 6
• Drug C 5 6 5 5 6 4 5 4 7

a) Is there an overall statistically significant difference in mean pain scores across the three formulations? Justify your results.

b) Based on the Tukey HSD test, which formulations are significantly different?

c) Use the two sample t-test to compare mean pain scores between drug A and drug C. Is there a statistically significant difference? Why or why not?

d) If the investigators compared each drug pair (A-B, A-C, B-C) using the above results and the Bonferroni adjustment, what conclusion would they draw concerning mean differences between Drug A and Drug B? Why?