size.supinf.mean.ps {statpsych}

Sample size for a paired-samples mean superiority or noninferiority test

Description

Computes the sample size required to perform a superiority or noninferiority test for the difference in population means with desired power in a paired-samples design. For a superiority test, specify the upper limit (h) for the range of practical equivalence and specify an effect size (es) such that es > h. For a noninferiority test, specify the lower limit (-h) for the range of practical equivalence and specify an effect size such that es > -h. Set the Pearson correlation planning value to the smallest value within a plausible range, and set the variance planning value to the largest value within a plausible range for a conservatively large sample size.

Usage

size.supinf.mean.ps(alpha, pow, var, es, cor, h)

Arguments

alpha

alpha level for hypothesis test

pow

desired power

var

planning value of average variance of the two measurements

es

planning value of mean difference

cor

planning value of the correlation between measurements

h

upper or lower limit for range of practical equivalence

Value

Returns the required sample size

Examples

size.supinf.mean.ps(.05, .80, 225, 9, .75, 4)

# Should return:
# Sample size
#          38