anova2way.se.unbal: Power calculation for test of simple effect for two-way...

In powertools: Power and Sample Size Tools

Power calculation for test of simple effect for two-way unbalanced analysis of variance

Description

Conducts power calculations for a test of a simple effect in a two-way unbalanced (unequal cell sizes) ANOVA. A "simple effect" is a contrast among the cell means. This function does not solve for sample size. For a test of a contrast in a balanced (equal cell sizes) two-way ANOVA, anova2way.se.bal can also be used and can solve for sample size. For a test of contrast among factor levels, see anova2way.c.unbal.

Usage

anova2way.se.unbal(
  nmatrix = NULL,
  mmatrix = NULL,
  cmatrix = NULL,
  sd = 0,
  Rsq = 0,
  ncov = 0,
  alpha = 0.05,
  sides = 2,
  v = FALSE
)

Arguments

nmatrix	A matrix of sample sizes (see example).
mmatrix	A matrix of group means (see example).
cmatrix	A matrix of contrast coefficients (see example).
sd	The estimated standard deviation within each group.
Rsq	The estimated R^2 for regressing the outcome on the covariates; defaults to 0.
ncov	The number of covariates adjusted for in the model; defaults to 0.
alpha	The significance level (type 1 error rate); defaults to 0.05.
sides	Either 1 or 2 (default) to specify a one- or two- sided hypothesis test.
v	Either TRUE for verbose output or FALSE (default) to output computed argument only.

Value

A list of the arguments (including the computed power).

Examples

nmatrix <- matrix(c(30, 30, 30, 30, 30, 30), nrow = 2, byrow = TRUE)
mmatrix <- matrix(c(9.3, 8.9, 8.5, 8.7, 8.3, 7.3), nrow = 2, byrow = TRUE)
cmatrix <- matrix(c(-1, 0, 0, 1, 0, 0), nrow = 2, byrow = TRUE)
anova2way.se.unbal(nmatrix = nmatrix, mmatrix = mmatrix, cmatrix = cmatrix,
sd = 2, alpha = 0.025)

powertools documentation built on April 4, 2025, 5:02 a.m.