Table 2.

Sample size and power calculations.

Alpha	Beta	k	Cluster size	Control group proportion	Intervention group proportion	Minimum clusters required	Resulting power
.01	.2	.25	32	0.25	0.15	18	0.808
.05	.2	.25	32	0.25	0.15	12	0.803
.01	.2	.25	40	0.25	0.15	16	0.818
.05	.2	.25	40	0.25	0.15	11	0.823
.01	.2	.25	32	0.3	0.15	10	0.842
.05	.2	.25	32	0.3	0.15	7	0.849
.01	.2	.25	40	0.3	0.15	9	0.851
.05	.2	.25	40	0.3	0.15	6	0.84