mHP.btilde: Compute the futility boundary (modified Haybittle-Peto) for...

Description Usage Arguments Details References

Description

The futility boundary btilde is computed by solving (under the alternative)

Usage

1
mHP.btilde(beta, cov.J)

Arguments

beta

the type II error

cov.J

the 3 x 3 covariance matrix

Details

P(\tilde{Z}_J^1≤\tilde{b} or \tilde{Z}_J^2≤\tilde{b}) = εβ

where the superscripts denote the stage and ε is the fraction of the type I error (α) spent and β is the type II error. We make use of the joint normal density of Z_{J} (the overall group) at each of the three stages and the fact that the \tilde{Z_J} is merely a translation of Z_J. So here the calculation is based on a mean of zero and has to be translated during use!

References

Adaptive Choice of Patient Subgroup for Comparing Two Treatments by Tze Leung Lai and Philip W. Lavori and Olivia Yueh-Wen Liao. Contemporary Clinical Trials, Vol. 39, No. 2, pp 191-200 (2014). http://www.sciencedirect.com/science/article/pii/S1551714414001311


ASSISTant documentation built on May 6, 2019, 1:02 a.m.