Sample size calculation for the Wilcoxon-Mann-Whitney test using the Noether formula.
noether(alpha, power, t, p, x1 = c(0), ties = FALSE)two sided type I error rate
power: detect a relative effect p at least with probability power
proportion of subjects in the first group (between 0 and 1)
relative effect
advance information is only needed in case of ties
TRUE if ties are possible (non continuous distribution), otherwise FALSE
Returns a data frame with the sample sizes for each group
Noether, G. E. (1987). Sample Size Determination for Some Common Nonparametric Tests. Journal of the American Statistical Association 85, 645.647.