Number of female and male chlamydia cases needed according to desired odds ratio and study power
| Women | Men | ||||||
|---|---|---|---|---|---|---|---|
| No of cases | Detectable odds ratio | No of cases | Detectable odds ratio | ||||
| Power | Power | ||||||
| Calculations based on a two sided significance level of 0.05 in univariate analysis ignoring matching. Frequency of exposure in controls 20%. | |||||||
| 80% | 90% | 95% | 80% | 90% | 95% | ||
| 170 | 1.89 | 2.06 | 2.20 | 114 | 2.16 | 2.39 | 2.59 |
| 220 | 1.75 | 1.89 | 2.00 | 146 | 1.98 | 2.18 | 2.33 |
| 280 | 1.65 | 1.76 | 1.86 | 197 | 1.81 | 1.96 | 2.06 |