For all sample size calculation, alpha = 0.05 (i.e the confidence level =95%), and the power is 80% (i.e. beta = 0.2).

Question 1 part A: To construct a 95% CI for a proportion (p) of 20% with margin of error = 2.5%, what is the minimum sample size required? (5 points)

Question 1 Part B: To construct a 95% CI for a mean with standard deviation of 15, margin of error = 3, and attrition =15%, how many patients are required to enroll? (5 points)

Question 1 Part C: To construct a 95% CI for a difference in means from two independent groups with standard deviation = 10.0, margin of error = 2.5, attrition = 15%, how many patients in each group should be enrolled? (5 points)