stat340: Data and functions for BIAS at NMBU

#' species: Plant Species Count Data
#'
#' This data contains the number of plant species in 90 plots of different
#' biomass and pH. The biomass is a continuous explanatory variable, the soil pH
#' is a categorical variable, and the response variable is the number of plant
#' species on each plot.
#'
#' @format A data frame with 90 observations (rows) and 3 variables (columns).
#' \tabular{llllr}{
#'   \tab \bold{Column name} \tab \bold{Data type} \tab \bold{Description} \tab \bold{Values}\cr
#'   \code{[,1]} \tab \code{pH} \tab factor \tab 3 levels of soil pH \tab (high, low, mid)\cr
#'   \code{[,2]} \tab \code{Biomass} \tab numeric \tab The biomass in the soil \tab (0.05017 - 9.98177)\cr
#'   \code{[,3]} \tab \code{Species} \tab integer \tab Number of plant species \tab (2 - 44)
#' }
#'
#' @examples
#'
#' # First six rows
#' head(species)
#'
#' # The relationship between biomass and plant species
#' plot(species$Biomass, species$Species, col = species$pH,
#'      pch = 19, xlab = "Biomass", ylab = "Plant species")
#'
#' @source `The R book`, M.J. Crawley, Wiley, 2007 (Chapter 14.3).
#'
#' @docType data
#' @keywords datasets
#' @name species
#' @usage species
#'
"species"