Table I.

The Number of Study Subjects Required to Show BE with 80% Power is a Function of Within-Subject Variability and GMR (Sample Size Estimations are for the Case σ _WT = σ _WR and σ _D = 0)

Within-subject %CV	GMR (%)	Sample size for a two-way crossover study	Sample size for a four-way fully replicated crossover
15	100	10	6
	105	12	8
	110	20	12
30	100	32	18
	105	38	20
	110	68	36
45	100	66	34
	105	80	42
	110	142	72
60	100	108	56
	105	132	66
	110	236	118
75	100	156	80
	105	190	96
	110	340	172