datums: Miscellaneous Data Sets

#' Price of Wheat in Delhi, 1763--1836
#' 
#' Price of wheat in Delhi 1763-1836.  This series was notoriously and spuriously related to sunspots (Wolf's numbers) by William S. Jevons in his last published paper. Jevons theorized that sunspots were related to commercial cycles and crises due to similarity in cycles of these time series.
#' 
#' @format A data frame with 74 rows and 4 columns.
#' 
#' \tabular{lll}{
#' name \tab type \tab description \cr
#' \code{year} \tab \code{"integer"} \tab Year \cr
#' \code{price} \tab \code{"integer"} \tab Price in rupees per 1,000 seers of wheat in Delhi \cr
#' \code{maximum} \tab \code{"logical"} \tab Indicator marking a price maxima in a cycle \cr
#' \code{crisis} \tab \code{"logical"} \tab Commercial crisis \cr
#' }
#' 
#' @source Jevons, W. Stanley. 1879. "Sun-Spots and Commercial Crises." \emph{Nature}. \href{https://dx.doi.org/10.1038/019588a0}{doi:10.1038/019588a0}.
#' 
#' @references Stigler, Stephen M. \emph{The Seven Pillars of Statistical Wisdom}
#' 
#' @references Jevons, W. Stanley. 1882. "The Solar-Commercial Cycle." \emph{Nature}. \href{https://dx.doi.org/10.1038/026226a0}{doi:10.1038/026226a0}.
#' 
#' @seealso \code{nonsense} for another example of spurious correlations.
"delhiwheat"