wzRfun: Walmes Zeviani's collection of functions

#' @name wzRfun
#' @title Walmes Zeviani's collection of functions
#' @docType package
#' @description An R package with functions written for general
#'     purpose. Most of these are related to the analysis of experiments
#'     and graphical representation with trellis based plots.
#' @details To not show the start up message, use
#'     \code{options(wzRfun_startup_message = FALSE)}.
#' @examples
#'
#' \dontrun{
#'
#' options(wzRfun_startup_message = FALSE)
#' library(wzRfun)
#'
#' detach(package:wzRfun)
#'
#' options(wzRfun_startup_message = NULL)
#' library(wzRfun)
#'
#' }
NULL

#' @name soybeanwp
#' @title Factorial experiment to evaluate the effect of potassium and
#'     water on the soybean yield
#' @description The tropical soils, usually poor in potassium (K),
#'     demand potassium fertilization when cultivated with soybean
#'     (\emph{Glycine max} L.)  to obtain satisfactory yields. The aim
#'     of this study was to evaluate the effects of K doses and soil
#'     humidity levels on soybean agronomic characteristics. The
#'     experiment was carried out in a greenhouse, in pots with two
#'     plants, containing 5 dm$^3$ of soil. The experimental design was
#'     completely randomized block with treatments in a 5 x 3 factorial
#'     arrangement. The K doses (\code{potassium}) were 0; 30; 60, 120
#'     and 180 mg dm\eqn{^{-3}} , and the soil humidity (\code{water})
#'     ranged from 35 to 40; 47.5 to 52.5; and 60 to 65\% of the total
#'     porosity (represented as the midpoint). The characteristics
#'     appraised were: grain yield (\code{yield}, grams per plot),
#'     weight of a hundred grains (\code{w100}, grams), total number of
#'     grains per plot (\code{tg}), K concentration in the grain
#'     (\code{Kgrain}, g kg\eqn{^{-1}}), number of viable and not viable
#'     pods (\code{nvp, nip}). Observation number 74 can be considered
#'     atypical and removed to do statistical analysis. although the
#'     experiment had been installed in blocks, the greenhouse had
#'     constant conditions for all plots and the management, like
#'     irrigation, during the experimental cycle was carried out with
#'     much care, so, the block effect can be considered null.
#' @details This experiment was done at Universidade Federal da Grande
#'     Dourados in Dourados, Mato Grosso do Sul, Brazil. The article
#'     based on this experiment can be accessed by the link
#'     \url{http://ccarevista.ufc.br/seer/index.php/ccarevista/article/view/1454}.
#'     Thanks for the authors by their collaboration and permission to use
#'     this data.
#' @format A data frame with data from an experiment that evaluated the
#'     effect of water and potassium levels on soybean yield.
#' @keywords datasets
"soybeanwp"