Approximates the power of a paired-samples t-test for a planned sample size

Computes the approximate power of a paired-samples t-test for a planned sample size. For a conservatively low power approximation, set the variance planning values to the largest values within their plausible ranges, set the correlation planning value to the smallest value within its plausible range, and set the effect size to a minimally interesting value. The variances of the two measurements can be unequal.

Usage

power.mean.ps(alpha, n, var1, var2, es, cor)

Arguments

alpha: alpha level for hypothesis test
n: planned sample size
var1: planning value of measurement 1 variance
var2: planning value of measurement 2 variance
es: planning value of mean difference
cor: planning value of correlation between measurements

Value

Returns the approximate power of the test

Examples

power.mean.ps(.05, 20, 10.0, 12.0, 2, .7)
#>      Power
#>  0.9074354

# Should return:
#     Power
# 0.9074354