powertools (version 1.0.0)

anova2way.F.bal: Power calculation for two-way balanced analysis of variance F tests

Description

Performs sample size and power calculations for F tests in a two-way ANOVA with balanced data (that is, equal cell sizes). For a given matrix of cell means, computes power or required cell size for each factor and for their interaction, if an interaction is present. For unbalanced data (unequal cell sizes), see anova2way.F.unbal.

Usage

anova2way.F.bal(
  n = NULL,
  mmatrix = NULL,
  sd = 1,
  Rsq = 0,
  ncov = 0,
  alpha = 0.05,
  power = NULL,
  v = FALSE
)

Value

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

Arguments

n

The sample size per cell

mmatrix

A matrix of cell means (see example).

sd

The estimated standard deviation within each cell; defaults to 1.

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.

power

The specified level of power.

v

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

Examples

mmatrix <- matrix(c(9.3, 8.9, 8.5, 8.7, 8.3, 7.9), nrow = 2, byrow = TRUE)
anova2way.F.bal(n = 30, mmatrix = mmatrix, sd = 2, alpha = 0.05)
mmatrix <- matrix(c(9.3, 8.9, 8.5, 8.7, 8.3, 7.3), nrow = 2, byrow = TRUE)
anova2way.F.bal(n = 30, mmatrix = mmatrix, sd = 2, alpha = 0.05)
mmatrix <- matrix(c(9.3, 8.9, 8.5, 8.7, 8.3, 7.9), nrow = 2, byrow = TRUE)
anova2way.F.bal(n = 30, mmatrix = mmatrix, sd = 2, Rsq = 0.4, ncov = 1, alpha = 0.05)