size.test.lc.mean.bs: Sample size for a test of a between-subjects mean linear...

In statpsych: Statistical Methods for Psychologists

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
 

statpsych documentation built on Sept. 11, 2024, 7:42 p.m.