[R] Generating repeated measures data

[Joshua Wiley]

Hi John,

This is not advanced enough for serious applications, but if you are
just looking for a simple way to make example data, you could do
something like:

gencor <- function(order, mu, sd, r) {
  X <- matrix(rnorm(prod(order), mean = mu, sd = sd), nrow = order[1],
ncol = order[2])
  R <- matrix(r, nrow = order[2], ncol = order[2])
  diag(R) <- 1
  X %*% chol(R)
}

cor(X <- gencor(c(100, 3), 10, 2, .5))

HTH,

Josh

On Fri, Mar 18, 2011 at 5:37 PM, John Sorkin
<jsorkin at grecc.umaryland.edu> wrote:
> How would one generate data to be used in a simulation of a repeated measures ANOVA given a known (1) within-person correlation with known (2) mean and SD of data obtained at each of three times of observation?
> Thanks,
> John
> John Sorkin
> Chief Biostatistics and Informatics
> Univ. of Maryland School of Medicine
> Division of Gerontology and Geriatric Medicine
> JSorkin at grecc.umaryland.edu
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