SSR.CP {esDesign} | R Documentation |
Calculate the N2
and the critical value C
in Sample Size
Re-estimation Procedure
Description
The SSR.CP()
is used to calculate the sample size required
at the second stage and the critical value used at the final analysis. In
addition, this function can also used to conduct the conditional power
analysis in terms of N2
Usage
SSR.CP(Z1 = NULL, delta = NULL, N1 = NULL, pstar, alpha, beta, N2 = NULL)
Arguments
Z1 |
The test statistic obtained at the interim analysis |
delta |
The standardized size of treatment effect, which can be estimated
by using |
N1 |
The sample size used at the first stage |
pstar |
The |
alpha |
The overall Type I error rate |
beta |
The |
N2 |
The pre-specified sample size used at the second stage, which is used to conduct the conditional power analysis |
Value
A list contains
N2 The pre-specified sample size used at the second stage, which is used to implement the conditional power analysis
Conditional.Power The value of conditional power given the value of
N2
in the conditional power analysisP.Value The corresponding P-Value used at the final analysis in the conditional power analysis
N2.CP The re-estimated sample size of
N2
to ensure an adequate conditional powerc.CP The estimated the critical value used at the final analysis based the conditional power
References
Proschan MA, Hunsberger SA. Designed extension of studies based on conditional power. Biometrics 1995:1315-1324. <doi:10.2307/2533262>
Examples
Z1 <- 1.527
delta <- 0.137
N1 <- 248
pstar <- 0.15
alpha <- 0.05
beta <- 0.2
res <- SSR.CP(Z1 = Z1, delta = delta, N1 = N1,
pstar = pstar, alpha = alpha, beta = beta)