Guidelines for Animal Number Selections

Guidelines for
Animal Numbers Selection

Statistical Assessments: A common reason for delay of protocol approval is inadequate statistical assessment .... or to say it another way, the protocol does not show how the required number of animals was determined.

The following table provides guidance in determining sample size for a given set of values:

	One Sample Test								Two sample Test
	Alpha = 0.05				Alpha = 0.01				Alpha = 0.05				Alpha = 0.01
	Beta =				Beta =				Beta =				Beta =
Estimated S/delta	0.01	0.05	0.10	0.20	0.01	0.05	0.10	0.20	0.01	0.05	0.10	0.20	0.01	0.05	0.10	0.20
4.0	296	211	170	128	388	289	242	191	588	417	337	252	770	572	478	376
2.0	76	54	44	34	100	75	63	51	148	106	86	64	194	145	121	96
1.5	44	32	26	20	58	54	37	30	84	60	49	37	110	82	69	55
1.0	21	16	13	10	28	22	19	16	38	27	23	17	50	38	32	26
0.8	14	11	9	8	19	15	13	11	25	18	15	12	33	25	21	17
0.67	11	8	7	6	15	12	11	9	18	13	11	9	24	18	15	13
0.5	7	6	5	4	10	8	8	7	11	8	7	6	14	11	10	8
0.4	6	5	4	4	8	7	6	6	8	6	5	4	10	8	7	6
0.33	5	4	4	3	7	6	6	5	6	5	4	4	8	6	6	5

Table taken from Text: Pharmaceutical Statistics (Practical & Clinical Applications) by Sanford Bolton