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sim.rasch <-function(persons, items, seed = NULL, cutpoint = "randomized")
{
#produces rasch homogeneous data
#cutpoint... probability or "randomized"
if (length(items) == 1) {
if (!is.null(seed)) set.seed(seed)
schwierig <- rnorm(items) #standard normal distributed
n.items <- items
} else {
schwierig <- items
n.items <- length(items)
}
if (length(persons) == 1) {
if (!is.null(seed)) set.seed(seed)
faehig <- rnorm(persons)
n.persons <- persons
} else {
faehig <- persons
n.persons <- length(persons)
}
fsmat <- outer(faehig, schwierig, "-")
psolve <- exp(fsmat)/(1+exp(fsmat))
if (cutpoint == "randomized") {
if (!is.null(seed)) set.seed(seed)
R <-(matrix(runif(n.items*n.persons),n.persons,n.items) < psolve)*1
} else {
R <- (cutpoint < psolve)*1
}
return(R)
}
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