#' Probability Reference Sample 1 with Bootstrap Replicate Weights (sp1_bootstrap)
#'
#' A replicate-weight version of \code{sp1}, including the main survey weight
#' and 500 bootstrap replicate weights. It is provided to illustrate
#' design-based variance estimation with \code{\link[survey]{svrepdesign}}.
#' The original primary sampling unit and stratum identifiers are not included.
#'
#' @format A data frame with 3494 rows and 512 columns. The first 12 columns
#'   are the substantive survey variables from \code{sp1} (\code{agecat},
#'   \code{marital}, \code{race}, \code{education}, \code{employment},
#'   \code{smoking}, \code{comorbidity}, \code{psa_level}, \code{BMI},
#'   \code{diabetes}, \code{pros_enlarged}, \code{wts_sp1}). The remaining
#'   500 columns are bootstrap replicate weights named \code{bw1} through
#'   \code{bw500} (numeric).
#'
#' @details
#' The bootstrap replicate weights were constructed from the original
#' stratified cluster design of \code{sp1}, using the Rao-Wu rescaling
#' bootstrap method. A total of \code{R = 500} replicates were
#' produced with \code{seed = 2026}.
#'
#' The variables \code{psu_sp1} and \code{strata_sp1} are not included in this
#' dataset because they are not needed when using replicate weights for
#' variance estimation. The main survey weight \code{wts_sp1} and the replicate
#' weight columns \code{bw1}--\code{bw500} are sufficient for constructing a
#' replicate-weight survey design object via \code{survey::svrepdesign()}.
#'
#' @source
#' Derived from \code{sp1} (National Health and Nutrition Examination Survey,
#' NHANES, 1999--2010 cycles), with bootstrap replicate weights added by the
#' package authors using the Rao-Wu rescaling bootstrap.
#'
#' @usage data(sp1_bootstrap)
#'
#' @examples
#' data(sp1_bootstrap)
#'
#' # Example: create replicate-weight survey design object
#' des_boot <- survey::svrepdesign(
#'   data    = sp1_bootstrap,
#'   weights = ~wts_sp1,
#'   repweights = "bw[0-9]+",
#'   type    = "bootstrap",
#'   combined.weights = FALSE
#' )
#'
#' summary(des_boot)
"sp1_bootstrap"
