computeNPlanBatchSafeZ {safestats}

Helper function: Computes the planned sample size based on the minimal clinical relevant mean difference, alpha and beta.

Description

Helper function: Computes the planned sample size based on the minimal clinical relevant mean difference, alpha and beta.

Usage

computeNPlanBatchSafeZ(
  meanDiffMin,
  alpha = 0.05,
  beta = 0.2,
  sigma = 1,
  kappa = sigma,
  alternative = c("twoSided", "greater", "less"),
  testType = c("oneSample", "paired", "twoSample"),
  tol = 1e-05,
  highN = 1e+06,
  ratio = 1,
  parameter = NULL,
  grow = TRUE
)

Arguments

meanDiffMin

numeric that defines the minimal relevant mean difference, the smallest population mean that we would like to detect.

alpha

numeric in (0, 1) that specifies the tolerable type I error control –independent on n– that the designed test has to adhere to. Note that it also defines the rejection rule e10 > 1/alpha.

beta

numeric in (0, 1) that specifies the tolerable type II error control necessary to calculate both "n" and "phiS". Note that 1-beta defines the power.

sigma

numeric > 0 representing the assumed population standard deviation used for the test.

kappa

the true population standard deviation. Default kappa=sigma.

alternative

a character string specifying the alternative hypothesis must be one of "twoSided" (default), "greater" or "less".

testType

either one of "oneSample", "paired", "twoSample".

tol

a number that defines the stepsizes between the lowParam and highParam.

highN

integer that defines the largest n of our search space for n. This might be the largest n that we are able to fund.

ratio

numeric > 0 representing the randomisation ratio of condition 2 over condition 1. If testType is not equal to "twoSample", or if nPlan is of length(1) then ratio=1.

parameter

optional test defining parameter. Default set to NULL.

grow

logical, default set to TRUE so the grow safe test is used in the design.

Value

a list which contains at least nPlan and the phiS, that is, the parameter that defines the safe test.