Sample size for a repeated-measures continuous endpoint

Comparison of the mean of n_measurements post-baseline measurements under a compound-symmetry correlation correlation between them. The effective variance is \(\sigma^2 [1 + (r-1)\rho]/r\), so more visits help most when the within-subject correlation is low.

Usage

sampleSizeRepeatedMeasures(
  delta,
  sd,
  n_measurements,
  correlation,
  power = 0.8,
  sig_level = 0.05,
  ratio = 1,
  sides = 2L,
  dropout = 0,
  cluster_size = NULL,
  icc = NULL
)

Arguments

delta, sd, power, sig_level, ratio, sides, dropout, cluster_size, icc

As in sampleSizeContinuous().

n_measurements

Number of post-baseline measurements per subject.

correlation

Compound-symmetry correlation between measurements (0-1).

Value

A trial_power object.

References

Frison & Pocock (1992), Stat Med.

See also

sampleSizeANCOVA()