Δ | loge(Δ) | bλ
c
|
N
| Pr(LCL>δ/2 |H1) | eCIW1 | Pr(UCL<δ/2 |H0) | dCIW0 |
---|
1.25 | 0.22 | 1.12 | aInitial | 1264 | 0.2925 | 0.322 | 0.2651 | 0.314 |
| | | cFinal | 5402 | 0.8241 | 0.155 | 0.8016 | 0.151 |
1.50 | 0.41 | 1.22 | aInitial | 384 | 0.2759 | 0.602 | 0.2658 | 0.577 |
| | | cFinal | 1694 | 0.8349 | 0.285 | 0.8039 | 0.273 |
1.75 | 0.56 | 1.32 | aInitial | 204 | 0.2766 | 0.850 | 0.2536 | 0.804 |
| | | cFinal | 938 | 0.8496 | 0.392 | 0.8021 | 0.371 |
2.00 | 0.69 | 1.41 | aInitial | 132 | 0.2700 | 1.087 | 0.2344 | 1.018 |
| | | cFinal | 632 | 0.8503 | 0.487 | 0.8052 | 0.457 |
- The ainitial N calculated using equation (5), Schoenfeld’s [14] formula, is the total sample size required to detect a hazard ratio Δ at the 5% level with 80% power, assuming equal subject allocation and a 0.5 overall censoring proportion. b λ
c
is the hazard rate for the exponential censoring time given by equation (7), and δ. = loge(Δ). The cfinal N is the total sample size such that both Pr(LCL > δ /2 | H1) and Pr(UCL < δ /2 | H0) are at least 0.8 as estimated by the proportion of times LCL and UCL are bounded by δ /2 in 10,000 iterations. dCIW0 and eCIW1 are the mean width of the 95% confidence intervals under H0 and H1, respectively.