trtools: Miscellaneous Tools for Teaching Statistics

#' Insulin assay.
#'
#' The data are from a study designed to determine if the effect of two insulins is additive or synergistic. 
#'
#' @format A data frame with 56 observations and four variables:
#' \describe{
#'    \item{y:}{conversion of (3-3H) glucose to toluene-extractable lipids in isolated rat fat cells}
#'    \item{insulin1:}{dose of standard insulin (pmol/liter)}
#'    \item{insulin2:}{dose of A1-B29 suberoyl insulin (pmol/liter)}
#'    \item{ratio:}{ratio of standard insulin to A1-B29 suberoyl insulin}
#' }
#' 
#' @details These data were featured in Darby and Ellis (1976) and also McCullagh and Nelder (1989). In particular see the latter for a discussion of a nonlinear gamma regression model for these data.
#'
#' @source Darby, S. C. & Ellis, M. J. (1976). A test of synergism between two drugs. \emph{Applied Statistics}, \emph{25}, 296-299.
#' 
#' McCullagh, P. & Nelder, J. A. (1989). \emph{Generalized linear models} (2nd Edition). Boca Raton: Chapman & Hall/CRC.
"insulin"