Dr Smith Wishes to Compare Three Widely Used Sleeping Preparations $H_0 and H_A$

Short Answer

Dr. Smith wishes to compare three widely used sleeping preparations with regard to possible "hangover" effects. Twelve volunteers are given a problem-solving test at 9:00 a.m. after having been administered the standard recommended dose of one of the preparations (according to random assignment) the night before. The results are given below.
(a) Give $H_0 and H_A$ . 
(b) Is there a significant treatment effect $(use \alpha = .05)$ ?
(c) If significant results are obtained in (b) use Tukey's HSD test (α = .05) to make all possible pairwise comparisons among the groups. Draw final conclusions.