#' Simulated efficiency dataset (100 DMUs)
#'
#' Dataset with 100 simulated decision-making units (DMUs) used to illustrate
#' the basic workflow of \pkg{PEAXAI} in a simple single-input/single-output
#' setting.
#'
#' Each DMU uses one input \code{x1} to produce an output \code{y}. The variable
#' \code{yD} represents the theoretical output on the deterministic frontier,
#' that is, the output level that would be observed in the absence of
#' technical inefficiency.
#'
#' @details
#' The dataset is purely simulated and is intended for examples and vignettes.
#' It contains 100 DMUs with heterogeneous input levels and corresponding
#' output levels. The observed output \code{y} can be interpreted as
#' \code{y <= yD}, where the gap between \code{yD} and \code{y} reflects
#' technical inefficiency (plus possible noise, depending on how the data
#' were generated).
#'
#' @format
#' A \code{data.frame} with 100 rows and 3 columns:
#' \describe{
#'   \item{x1}{Input of the DMU (e.g., resource use, cost or effort).}
#'   \item{y}{Observed output, potentially affected by technical inefficiency.}
#'   \item{yD}{Deterministic (theoretical) output on the efficient frontier.}
#' }
#'
#' @source
#' Simulated data generated by the authors for illustrative purposes.
#'
#' @examples
#' data(data)
#' str(data)
#' summary(data)
#'
#' if (requireNamespace("ggplot2", quietly = TRUE)) {
#'   ggplot2::ggplot(data, ggplot2::aes(x = x1)) +
#'     ggplot2::geom_point(ggplot2::aes(y = y), alpha = 0.6) +
#'     ggplot2::geom_line(ggplot2::aes(y = yD), color = "red") +
#'     ggplot2::labs(
#'       x = "Input x1",
#'       y = "Output",
#'       title = "Simulated DMUs and theoretical frontier"
#'     ) +
#'     ggplot2::theme_minimal()
#' }
#'
#' @docType data
#' @name data
#' @usage data(data)
#' @keywords datasets
"data"
