#' X-bar and R control charts #' #' This function builds the X-bar and R control charts in the same window. #' #' #' @param x The data to be plotted. #' @param sizes A value or a vector of values specifying the sample sizes #' associated with each group. #' @return Return the two control charts. #' @export #' @author Daniela R. Recchia, Emanuel P. Barbosa. #' @examples #' #' data(pistonrings) #' attach(pistonrings) #' cchart.Xbar_R(pistonrings[1:25, ]) #' cchart.Xbar_R <- function(x, sizes) { par(mfrow = c(1, 2)) # setup 1 row and 2 columns for plotting qcc(x, type = "xbar", add.stats = F) qcc(x, type = "R", add.stat = F) }