February, 2003
© 2000, 2001, 2003 Scott S. Emerson, M.D., Ph.D.
Determining the sample size (cont.)
Fixed sample test (no interim analyses):
·d
= (z1-a + zb) for size a,
power b
Two sample test of binomial proportions
·D
= (pT1 - pC1)
- (pT0 - pC0)
·V = pT1 (1 - pT1) + pC1 (1 - pC1) under H1
·n = sample size per arm