noiris: Data sets

#' PISA data.
#'
#' PISA is the OECD's Programme for International Student Assessment. Every
#' three years it tests 15-year-old students from all over the world in reading,
#' mathematics and science. The tests are designed to gauge how well the
#' students master key subjects in order to be prepared for real-life situations
#' in the adult world.
#'
#' @format The main data frame \code{pisa} has 216 rows and 12 variables:
#' \describe{
#'   \item{country}{factor with 36 levels, including the International average}
#'   \item{continent}{factor with 5 levels}
#'   \item{year}{ranges from 2000 to 2015 in increments of 3}
#'   \item{math}{PISA math score}
#'   \item{reading}{PISA reading score}
#'   \item{science}{PISA science score}
#'   \item{interest_sci}{PISA interest in science score - 2006 only}
#'   \item{support_sci}{PISA support for science score - 2006 only}
#'   \item{lifeExp}{life expectancy at birth, in years}
#'   \item{pop}{population}
#'   \item{gdpPercap}{GDP per capita (US$, inflation-adjusted)}
#'   \item{giniPercap}{Gini coefficient of inequality}
#'   }
#'
#' @details The PISA data has been linked to the \link{gapminder_2019} data.
#'   Not all countries have PISA scores for all years. Interest and support for
#'   science were only measured in 2006.
#'
#' @source \url{https://www.oecd.org/pisa/}
#' @seealso \link[gapminder]{gapminder}
#' @examples
#' library(noiris)
#' str(pisa)
#' pisa
#'
"pisa"