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.

For more details, see Section 3.25 of Bonett (2021, Volume 1)

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

References

\insertRef

Bonett2021statpsych

Examples

v <- c(1/4, 1/4, 1/4, 1/4, -1)
size.test.lc.mean.bs(.05, .90, 1, .5, v)

# Should return:
# Sample size per group
#                    53

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 Jan. 13, 2026, 1:07 a.m.