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Relationship between Precision and width of Confidence Interval (CI)
| Prevalence in Sample | Absolute Precision | 95% CI for Population | CI Width | Required Sample size |
|---|---|---|---|---|
| 25% | ± 2% | (23%, 27%) | 4% | 1801 |
| 25% | ± 5% | (20%, 30%) | 10% | 289 |
| 25% | ± 10% | (15%, 35%) | 20% | 73 |
| 30% | ± 2% | (28%, 32%) | 4% | 2017 |
| 30% | ± 5% | (25%, 35%) | 10% | 323 |
| 30% | ± 10% | (20%, 40%) | 20% | 81 |
