Table 2 Recommended precision for expected prevalence
From: Sample size calculation for prevalence studies using Scalex and ScalaR calculators
| Â | EP | Recommended Precision | |||
Large Scale | Small Scale | Preliminary Study | Remark | ||
1 | 10 to 90% | 2 ~ 3% | 4 ~ 5% |  > 5% |  |
2 |  < 10% | 0.25*EP | 0.50*EP |  > 0.50*EP | Cannot be equal to EP or larger |
|  | e.g. 4% | 1% | 2% |  > 2% | Cannot be 4% or larger |
3 |  > 90% | 0.25*(100-EP) | 0.5*(100-EP) |  > 0.5*(100-EP) | Cannot be (100-EP) or larger |
|  | e.g. 95% | 1.25% | 2.5% |  > 2.5% | Cannot be 5% or larger |