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ASSISTant (version 1.4.3)

mHP.b: Compute the efficacy boundary (modified Haybittle-Peto) for the first two stages

Description

Compute the efficacy boundary (modified Haybittle-Peto) for the first two stages

Usage

mHP.b(prevalence, N, cov.J, mu.prime, Sigma.prime, alpha, btilde, theta)

Arguments

prevalence

the vector of prevalences between 0 and 1 summing to 1. \(J\), the number of groups, is implicitly the length of this vector and should be at least 2.

N

a three-vector of total sample size at each stage

cov.J

the 3 x 3 covariance matrix for Z_J at each of the three stages

mu.prime

a list of \(J\) mean vectors, each of length \(J-1\) representing the conditional means of all the other \(Z_j\) given \(Z_i\). This mean does not account for the conditioned value of \(Z_i\) and so has to be multiplied by that during use!

Sigma.prime

a list of \(J\) covariance matrices, each \(J-1\) by \(J-1\) representing the conditional covariances all the other \(Z_j\) given \(Z_i\)

alpha

the amount of type I error to spend

btilde

the futility boundary

theta

the effect size on the probability scale