Table 7.

This table shows the minimum sample size required in each group to achieve the given power for detecting the inequality in population proportions when the level of significance is α = 0.05 in all cases. This is for a two-sided two-sample proportion test.

p1	p2	Sample Size in Each Group (Power = 0.70)	Sample Size in Each Group (Power = 0.80)	Sample Size in Each Group (Power = 0.90)
0.10	0.15	540	686	918
0.10	0.20	157	199	266
0.10	0.25	79	100	133
0.20	0.25	861	1094	1464
0.20	0.30	231	294	392
0.20	0.35	109	138	185
0.30	0.35	1083	1377	1842
0.30	0.40	281	356	477
0.30	0.45	128	163	217