Power of Fisher's Exact Test for Comparing Proportions

Calculate by simulation the power of Fisher's exact test for comparing two proportions given two margin counts.

power.fisher.test(p1, p2, n1, n2, alpha=0.05, nsim=100, alternative="two.sided")

Arguments

p1: first proportion to be compared.
p2: second proportion to be compared.
n1: first sample size.
n2: second sample size.
alpha: significance level.
nsim: number of data sets to simulate.
alternative: indicates the alternative hypothesis and must be one of "two.sided", "greater" or "less".

Details

Estimates the power of Fisher's exact test for testing the null hypothesis that p1 equals p2 against the alternative that they are not equal.

The power is estimated by simulation. The function generates nsim pairs of binomial deviates and calls fisher.test to obtain nsim p-values. The required power is tnen the proportion of the simulated p-values that are less than alpha.

Value

Estimated power of the test.

Author

Gordon Smyth

Examples