R/daphniastrat.R

In trobinj/trtools: Miscellaneous Tools for Teaching Statistics

#' Stratified random sample of daphnia counts.
#'
#' These data are from a stratified random sample from three layers of a lake: epilimnion, thermocline, and hypolimnion. The volumes of these layers are approximately 100kL, 200kL, and 400kL respectively, so that the sampling fractions are 1/7, 2/7, and 4/7, respectively. The sampling units are one liter containers of water, and the target variable is daphnia per liter.
#'
#' @format A data frame with 45 observations and two variables:
#' \describe{
#'    \item{layer:}{layer from which the water sample was taken}
#'    \item{count:}{number of daphnia in the liter of water}
#' }
#'
#' @source Barrett, J. P. & Nutt, M. E. (1979). \emph{Survey sampling in the environmental sciences: A computer approach}. Wentworth, NH: COMPress, Inc.
#'
#' Gregoire, T. G. & Valentine, H. T. (2007). \emph{Sampling strategies for natural resources and the environment}. Boca Raton, FL: Chapman & Hall/CRC.
"daphniastrat"