power.ranksum {FDRsampsize}

Compute power of the rank-sum test

Description

Compute power of rank-sum test;Uses formula of Noether (JASA 1987)

Usage

power.ranksum (n, alpha, p) 

Arguments

n

sample size (scalar)

alpha

p-value threshold (scalar)

p

Pr (Y>X), as in Noether (JASA 1987)

Details

In most applications, the null effect size will be designated by p = 0.5, which indicates that Thus, in the example below, the argument null.effect=0.5 is specified in the call to fdr.sampsize.

Value

vector of power estimates for two-sided tests

References

Noether, Gottfried E (1987) Sample size determination for some common nonparametric tests. Journal of the American Statistical Association, 82:645-647.

Examples

 power.ranksum        # show the power function
 res=fdr.sampsize(fdr=0.1,
                  ave.pow=0.8,
                  pow.func=power.ranksum,
                  eff.size=rep(c(0.8,0.5),c(100,900)),
                  null.effect=0.5)
 res