blindrecalc: adjusted_alpha.Student – R documentation

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adjusted_alpha.Student

Adjusted level of significance

Description

This method returns an adjusted significance level that can be used such that the actual type I error rate is preserved.

Usage

## S4 method for signature 'Student'
adjusted_alpha(design, n1, nuisance, tol, iters = 10000, seed = NULL, ...)

Arguments

`design`	Object of class `Student` created by `setupStudent`.
`n1`	Either the sample size of the first stage (if `recalculation = TRUE` or the toal sample size (if `recalculation = FALSE`).
`nuisance`	Value of the nuisance parameter. For the Student's t-test this is the variance.
`tol`	desired absolute tolerance
`iters`	Number of simulation iterations.
`seed`	Random seed for simulation.
`...`	Further optional arguments.

Details

The method is only vectorized in either nuisance or n1.

In the case of the Student's t-test, the adjusted alpha is calculated using the algorithm by Kieser and Friede (2000): "Re-calculating the sample size in internal pilot study designs with control of the type I error rate". Statistics in Medicine 19: 901-911.

Value

Value of the adjusted significance level for every nuisance parameter and every value of n1.

Examples

d <- setupStudent(alpha = .025, beta = .2, r = 1, delta = 0, delta_NI = 1.5, n_max = 848)
sigma <- c(2, 5.5, 9)
adjusted_alpha(design = d, n1 = 20, nuisance = sigma, tol = 1e-4, iters = 1e3)

blindrecalc

Blinded Sample Size Recalculation

v0.1.2

MIT + file LICENSE

Authors

Lukas Baumann [aut], Maximilian Pilz [aut, cre], Institute of Medical Biometry and Informatics - University of Heidelberg [cph]

Initial release