1. Suppose we are planning a new study similar in design to study 1. How many participants do we need to study to detect an underlying 3-mm Hg treatment effect for SBP with 80% power assuming there is no carry-over effect and we perform a two-sided test with α = .05? 

2. Answer Problem 13.58 for an underlying 2-mm Hg treatment effect for DBP?

3. Answer Problem 13.58 for a new study similar in design to study 2?

Three separate two-period cross-over studies were performed, based on different groups of subjects. Study 1 compared 0.625 mg estrogen with placebo. Study 2 compared 1.25 mg estrogen with placebo. Study 3 compared 1.25 mg estrogen with 0.625 mg estrogen. Subjects received treatment for 4 weeks in each active-treatment period; a 2-week washout period separated the two active-treatment periods.