|
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.
