[22] 2. The data 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: Treatment Block A B C D 1 6 10 8 9 2 4 9 5 7 3 12 15 14 14 a) Do the data present sufficient evidence to indicate differences among the treatment means? Test using a = 0.05. b) Do the data present sufficient evidence to indicate differences among the block means? Test using a = 0.05. c) Use Tukey's method for paired comparisons to determine which of the treatment means differ significantly from the others. Test using a = 0.05