Table 2 Margin of error* (95% confidence interval) according to sample size and prevalence of the condition
Sample size (n) | Prevalence of condition | ||||
|---|---|---|---|---|---|
50% | 30% | 10% | 3% | 1% | |
10 | 31.6 | 29.0 | 19.0 | 10.8 | 6.3 |
20 | 22.4 | 20.5 | 13.4 | 7.6 | 4.4 |
50 | 14.1 | 13.0 | 8.5 | 4.8 | 2.8 |
100 | 10.0 | 9.2 | 6.0 | 3.4 | 2.0 |
200 | 7.1 | 6.5 | 4.2 | 2.4 | 1.4 |
500 | 4.4 | 4.1 | 2.7 | 1.5 | 0.9 |
1,000 | 3.2 | 2.9 | 1.9 | 1.1 | 0.6 |
2,000 | 2.2 | 2.0 | 1.3 | 0.8 | 0.4 |
5,000 | 1.4 | 1.3 | 0.8 | 0.5 | 0.3 |
10,000 | 1.0 | 0.9 | 0.6 | 0.3 | 0.2 |