2. Consider a balanced, completely randomized clinical trial in which 40 patients with moderately high blood pressure are randomly assigned to four treatment groups:

Group 1 : nothing

Group 2 : placebo

Group 3 : Drug A

Group 4 : Drug B

Drug A is very well known, and treating patients with Drug A is the accepted practice in the medical profession. Drug B is a new, experimental drug whose developers believe could be more effective than Drug A. The response Y is the decrease in blood pressure over the study period. The measured responses for these 4 groups are summarized below.

i n Yi (mean) Si^2(variance)

1 10 10.69 0.830

2 10 12.17 0.894

3 10 11.95 0.510

4 10 11.82 0.741

(a) Find the estimated coefficients from the model

Y=0+1X1+2X2+3X3+e

whereX1,X2andX3are dummy codes for groups 1, 2 and 3, and group4 is the reference group.

(b) construct ANOVA table.