even4void

itan <- function(x, keys=NULL, digits=3, no.resp=4) {
  # x is an n subjects by k items matrix
  # keys is a vector with the correct keys (A, B, C, D)
  stopifnot(ncol(x)>1)
  if (is.null(keys)) keys <- rep("A", ncol(x))
  require(ltm)
  raw.resp <- matrix(nr=ncol(x), nc=no.resp)
  colnames(raw.resp) <- LETTERS[1:no.resp]
  for (i in 1:ncol(x)) {
    tmp <- table(x[,i])