A more efficient experiment than the one described in problem 9-62 was carried out to determine whether a sleeping pill was effective. Each person in a random sample of 30 people was given the three treatments: drug, placebo, nothing. The order in which these treatments were administered was randomly chosen for each person in the sample.
a. Explain why this experiment is more efficient than the one described for the same investigation in problem 9-62. What is the name of the experimental design used here? Are there any limitations to the present method of analysis?
b. The results of the analysis include SSTR = 44,572, SSBL = 38,890, and SSE = 112,672. Carry out the analysis, and state your conclusions. Use α = 0.05.