lbdatasets: Miscellaneous datasets

#' Acute Leukemia data from Freireich et al (1963).
#'
#'  In this study there were 21 pairs of subjects, and within each
#'  pair one subject received 6-mercaptopurine (6-MP) and one got
#'  placebo. The data are right censored.
#'
#'  See also Gehan (1965) who used the data ignoring the pairing so
#'  that he could illustrate his famous two-sample (non-paired) rank
#'  test.
#'
#' @format   A data frame with 42 observations on the following variables.
#'  \describe{
#'    \item{\code{time}}{time in remission (in weeks)}
#'    \item{\code{status}}{event status, 1 is relapse, 0 is censored}
#'    \item{\code{treatment}}{treatment group: either 'placebo' or '6-MP'}
#'    \item{\code{pair}}{pair id number}
#' }
#' @source bpcp package
#' @references
#' Gehan (1965) Biometrika 52:203-223.
#' Freireich et al (1963) Blood 21(6):699-716.
#' @examples
#' head(frei)
"frei"