A pharmaceutical manufacturer wants to investigate the bioactivity of a new drug. A completely randomized single-factor experiment was conducted with three dosage levels, and the following results were obtained. Dosage Observations 2'0 3 24 23 3? 30 30 g 3? 44 31 35 40 g 42 4? 52 38 (a) Is there evidence to indicate that dosage level affects bioactivity? Use alpha = 0.05. (b) If it is appropriate to do so, make comparisons between the pairs of means using Tukey's test. What conclusions can you draw? (c) Analyze the residuals from this experiment and comment on model adequacy