powertools (version 1.0.0)

anova2way.F.unbal: Power calculation for two-way unbalanced analysis of variance F tests

Description

Performs sample size and power calculations for F tests in a two-way ANOVA with unbalanced data (that is, unequal sized cells). For given matrix of cell means and matrix of cell sample sizes, computes power for each factor and for their interaction, if an interaction is present. This function does not solve for cell sizes. For balanced data (equal cell sizes), see anova2way.F.unbal, which can solve for cell size.

Usage

anova2way.F.unbal(
  nmatrix = NULL,
  mmatrix = NULL,
  sd = NULL,
  Rsq = 0,
  ncov = 0,
  alpha = 0.05,
  v = FALSE
)

Value

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

Arguments

nmatrix

A matrix of cell sample sizes (see example).

mmatrix

A matrix of cell means (see example).

sd

The estimated standard deviation within each cell

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.

v

Either TRUE for verbose output or FALSE (default) to output computed argument only.

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, 7.9), nrow = 2, byrow = TRUE)
anova2way.F.unbal(nmatrix = nmatrix, mmatrix = mmatrix, sd = 2, alpha = 0.05)
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)
anova2way.F.unbal(nmatrix = nmatrix, mmatrix = mmatrix, sd = 2, alpha = 0.05)
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, 7.9), nrow = 2, byrow = TRUE)
anova2way.F.unbal(nmatrix = nmatrix, mmatrix = mmatrix, sd = 2, Rsq = 0.4^2,
ncov = 1, alpha = 0.05)