adjusted_alpha,Studentmethod {blindrecalc}  R Documentation 
This method returns an adjusted significance level that can be used such that the actual type I error rate is preserved.
## S4 method for signature 'Student'
adjusted_alpha(design, n1, nuisance, tol, iters = 10000, seed = NULL, ...)
design 
Object of class 
n1 
Either the sample size of the first stage (if

nuisance 
Value of the nuisance parameter. For the Student's ttest this is the variance. 
tol 
desired absolute tolerance 
iters 
Number of simulation iterations. 
seed 
Random seed for simulation. 
... 
Further optional arguments. 
The method is only vectorized in either nuisance
or n1
.
In the case of the Student's ttest, the adjusted alpha is calculated using the algorithm by Kieser and Friede (2000): "Recalculating the sample size in internal pilot study designs with control of the type I error rate". Statistics in Medicine 19: 901911.
Value of the adjusted significance level for every nuisance parameter and every value of n1.
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 = 1e4, iters = 1e3)