Suppose in a randomized block experiment designed to investigate the efficacy of four drugs for reducing the duration of migraine headaches, the observed ????-ratio for testing the equality of the treatment means is significant (???? = 0.003). Use the treatment means given in Table 12.37 to answer the following questions.

(a) Determine the number of pairwise comparisons that must be carried to separate the treatment means.

(b) Determine the degrees of freedom for the experimental error.

(c) Determine the Bonferroni distance ???? when the experimentwise error rate is

???????? = 0.06 and ???????????? = 156.3.

(d) Using the Bonferroni procedure, separate the treatment means and summarize using the underline notation.

(e) Compute a 95% confidence interval for the difference of the treatment A and B means.