Table 2.

Sample size and power (2-sided α=.05).

Power	Effect size	Sample size per group	Overall sample size	Overall sample size considering 15% attrition	Overall sample size considering 20% attrition
0.8	0.32	154	308	362	386
0.8	0.36	122	244	288	306
0.8	0.4	99	198	234	248
0.85	0.32	176	352	414	440
0.85	0.36	139	278	328	348
0.85	0.4	113	226	266	284