\HeaderA{HairEyeColor}{Hair and Eye Color of Statistics Students}{HairEyeColor}
\keyword{datasets}{HairEyeColor}
\begin{Description}\relax
Distribution of hair and eye color and sex in 592 statistics students.
\end{Description}
\begin{Usage}
\begin{verbatim}HairEyeColor\end{verbatim}
\end{Usage}
\begin{Format}\relax
A 3-dimensional array resulting from cross-tabulating 592 observations
on 3 variables.  The variables and their levels are as follows:

\Tabular{rll}{
No & Name & Levels \\
1 & Hair & Black, Brown, Red, Blond \\
2 & Eye & Brown, Blue, Hazel, Green \\
3 & Sex & Male, Female
}
\end{Format}
\begin{Details}\relax
The Hair \eqn{\times}{x} Eye table comes rom a survey of students at
the University of Delaware reported by Snee (1974).  The split by
\code{Sex} was added by Friendly (1992a) for didactic purposes.

This data set is useful for illustrating various techniques for the
analysis of contingency tables, such as the standard chi-squared test
or, more generally, log-linear modelling, and graphical methods such
as mosaic plots, sieve diagrams or association plots.
\end{Details}
\begin{Source}\relax
\url{http://euclid.psych.yorku.ca/ftp/sas/vcd/catdata/haireye.sas}

Snee (1974) gives the two-way table aggregated over \code{Sex}.  The
Sex split of the \sQuote{Brown hair, Brown eye} cell was changed in
\R{} 2.6.0 to agree with that used by Friendly (2000).
\end{Source}
\begin{References}\relax
Snee, R. D. (1974)
Graphical display of two-way contingency tables.
\emph{The American Statistician}, \bold{28}, 9--12.

Friendly, M. (1992a)
Graphical methods for categorical data.
\emph{SAS User Group International Conference Proceedings}, \bold{17},
190--200.
\url{http://www.math.yorku.ca/SCS/sugi/sugi17-paper.html}

Friendly, M. (1992b)
Mosaic displays for loglinear models.
\emph{Proceedings of the Statistical Graphics Section},
American Statistical Association, pp. 61--68.
\url{http://www.math.yorku.ca/SCS/Papers/asa92.html}

Friendly, M. (2000)
\emph{Visualizing Categorical Data.}
SAS Institute, ISBN 1-58025-660-0.
\end{References}
\begin{SeeAlso}\relax
\code{\LinkA{chisq.test}{chisq.test}},
\code{\LinkA{loglin}{loglin}},
\code{\LinkA{mosaicplot}{mosaicplot}}
\end{SeeAlso}
\begin{Examples}
\begin{ExampleCode}
require(graphics)
## Full mosaic
mosaicplot(HairEyeColor)
## Aggregate over sex (as in Snee's original data)
x <- apply(HairEyeColor, c(1, 2), sum)
x
mosaicplot(x, main = "Relation between hair and eye color")
\end{ExampleCode}
\end{Examples}

