The data that follow are observations collected from an experiment that compared four treatments, A, B, C, and D, within each of three blocks, using a randomized block design.

a. Do the data present sufficient evidence to indicate differences among the treatment means? Test using a = .05.
b. Do the data present sufficient evidence to indicate differences among the block means? Test using a = .05.
c. Rank the four treatment means using Tukey's method of paired comparisons with a .01.
d. Find a 95% confidence interval for the difference in means for treatments A and B.
e. Does it appear that the use of a randomized block design for this experiment was justified? Explain.

Treatment Block A B C DTotal 6 10 89 12 15 4 14 Total 22 34 2730 113 25