Table 3.
Stage | 1 | 2 |
Information rate | 50% | 100% |
Efficacy boundary (z-value scale) | 2.963 | 1.969 |
Overall power | 0.1641 | 0.8000 |
No of subjects | 61.8 | 123.7 |
Cumulative alpha spent | 0.0031 | 0.0500 |
Two-sided local significance level | 0.0031 | 0.0490 |
Lower efficacy boundary (t) | −0.377 | −0.172 |
Upper efficacy boundary (t) | 0.277 | 0.148 |
Sequential analysis with a maximum of 2 looks (group sequential design). The sample size was calculated for a two-sample test for rates (two sided), H0: pi(1) − pi(2) = 0, H1; treatment rate pi(1) = 0.9, control rate pi(2) = 0.7. (t): approximate treatment effect scale.