size.test.lc.mean.bs {statpsych} | R Documentation |
Sample size for a test of a between-subjects mean linear contrast
Description
Computes the sample size in each group (assuming equal sample sizes) required to test a linear contrast of population means with desired power in a between-subjects design. Set the variance planning value to the largest value within a plausible range for a conservatively large sample size.
Usage
size.test.lc.mean.bs(alpha, pow, var, es, v)
Arguments
alpha |
alpha level for hypothesis test |
pow |
desired power |
var |
planning value of average within-group variance |
es |
planning value of linear contrast of means |
v |
vector of between-subjects contrast coefficients |
Value
Returns the required sample size for each group
Examples
v <- c(1, -1, -1, 1)
size.test.lc.mean.bs(.05, .90, 27.5, 5, v)
# Should return:
# Sample size per group
# 47
[Package statpsych version 1.6.0 Index]