R/anscombe_outlier.R

In quartets: Datasets to Help Teach Statistics

#' Anscombe's Quartet Outlier Data
#'
#' This dataset contains 11 observations generated by Francis Anscombe to
#' demonstrate that statistical summary measures alone cannot capture the full
#' relationship between two variables (here, `x` and `y`). Anscombe emphasized
#' the importance of visualizing data prior to calculating summary statistics.
#'
#'  This Dataset has a linear relationship between `x` and `y` with a single
#'  outlier
#'
#' Additionally, the following statistical summaries hold:
#'  * mean of `x`: 9
#'  * variance of `x`: 11
#'  * mean of `y`: 7.5
#'  * variance of y: 4.125
#'  * correlation between `x` and `y`: 0.816
#'  * linear regression between `x` and `y`: `y = 3 + 0.5x`
#'  * \eqn{R^2} for the regression: 0.67
#'
#' @references Anscombe, F. J. (1973). "Graphs in Statistical Analysis".
#'   American Statistician. 27 (1): 17–21. doi:10.1080/00031305.1973.10478966.
#'   JSTOR 2682899.
#'
#' @format A dataframe with 11 rows and 2 variables:
#'
#' * `x`: the x-variable
#' * `y`: the y-variable
"anscombe_outlier"