Ho: p1-p2 ? margin Ha: p1-p2 > margin
if margin >0, the rejection of Null Hypothesis indicates the true rate p1 is superior over the reference value p2;
if margin <0, the rejection of the null hypothesis implies the true rate p1 is non-inferior against the reference value p2.
significance level
power = 1-beta
the mean response rate for test drug
the rate for reference drug
k=n1/n2
delta=p1-p2
the superiority or non-inferiority margin
Chow SC, Shao J, Wang H. Sample Size Calculation in Clinical Research. New York: Marcel Dekker, 2003