Power and Sample Size for One-Way Repeated Measures ANOVA Contrast

Source: R/getDesignMeans.R

Obtains the power and sample size for a single contrast in one-way repeated measures analysis of variance.

getDesignRepeatedANOVAContrast(
  beta = NA_real_,
  n = NA_real_,
  ngroups = 2,
  means = NA_real_,
  stDev = 1,
  corr = 0,
  contrast = NA_real_,
  meanContrastH0 = 0,
  rounding = TRUE,
  alpha = 0.025
)

Arguments

beta

The type II error.

n

The total sample size.

ngroups

The number of treatment groups.

means

The treatment group means.

stDev

The total standard deviation.

corr

The correlation among the repeated measures.

contrast

The coefficients for the single contrast.

meanContrastH0

The mean of the contrast under the null hypothesis.

rounding

Whether to round up sample size. Defaults to 1 for sample size rounding.

alpha

The one-sided significance level. Defaults to 0.025.

Value

An S3 class designRepeatedANOVAContrast object with the following components:

  • power: The power to reject the null hypothesis for the treatment contrast.

  • alpha: The one-sided significance level.

  • n: The number of subjects.

  • ngroups: The number of treatment groups.

  • means: The treatment group means.

  • stDev: The total standard deviation.

  • corr: The correlation among the repeated measures.

  • contrast: The coefficients for the single contrast.

  • meanContrastH0: The mean of the contrast under the null hypothesis.

  • meanContrast: The mean of the contrast under the alternative hypothesis.

  • effectsize: The effect size.

  • rounding: Whether to round up sample size.

Author

Kaifeng Lu, kaifenglu@gmail.com

Examples


(design1 <- getDesignRepeatedANOVAContrast(
  beta = 0.1, ngroups = 4, means = c(1.5, 2.5, 2, 0),
  stDev = 5, corr = 0.2, contrast = c(1, 1, 1, -3)/3,
  alpha = 0.025))
#>   alpha     power  n ngroups stDev corr meanContrastH0 meanContrast effectsize
#> 1 0.025 0.9012156 71       4     5  0.2              0            2       0.15