Table 1.

Sample sizes required for a population (N) to detect at least one infected animal assuming a prevalence (P), with 95% confidence

N	P
	0.5	0.4	0.3	0.25	0.2	0.15	0.1	0.05	0.02	0.01	0.005	0.001
10	4	5	6	7	8	9	10	10	10	10	10	10
20	5	6	8	9	10	13	16	20	20	20	20	20
50	5	7	9	10	13	16	22	35	48	50	50	50
100	5	7	9	11	14	18	26	45	78	96	100	100
200	5	7	9	11	14	19	27	51	105	156	191	200
300	5	7	9	11	14	19	28	54	118	190	260	300
400	5	7	9	11	14	19	28	55	125	211	311	400
500	5	7	9	11	14	19	29	56	129	225	349	500
600	5	7	9	11	14	19	29	57	132	236	379	597
700	5	7	9	11	14	19	29	57	134	243	403	691
800	5	7	9	11	14	19	29	57	136	250	422	782
900	5	7	9	11	14	19	29	58	138	255	437	868
1000	5	7	9	11	14	19	29	58	139	259	451	951