+----------------+-------------------+
| HairEyeColor   | R Documentation   |
+----------------+-------------------+

Hair and Eye Color of Statistics Students
-----------------------------------------

Description
~~~~~~~~~~~

Distribution of hair and eye color and sex in 592 statistics students.

Usage
~~~~~

::

    HairEyeColor

Format
~~~~~~

A 3-dimensional array resulting from cross-tabulating 592 observations
on 3 variables. The variables and their levels are as follows:

+------+--------+-----------------------------+
| No   | Name   | Levels                      |
+------+--------+-----------------------------+
| 1    | Hair   | Black, Brown, Red, Blond    |
+------+--------+-----------------------------+
| 2    | Eye    | Brown, Blue, Hazel, Green   |
+------+--------+-----------------------------+
| 3    | Sex    | Male, Female                |
+------+--------+-----------------------------+

Details
~~~~~~~

The Hair *x* Eye table comes rom a survey of students at the University
of Delaware reported by Snee (1974). The split by ``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.

Source
~~~~~~

`http://euclid.psych.yorku.ca/ftp/sas/vcd/catdata/haireye.sas <http://euclid.psych.yorku.ca/ftp/sas/vcd/catdata/haireye.sas>`_

Snee (1974) gives the two-way table aggregated over ``Sex``. The Sex
split of the ‘Brown hair, Brown eye’ cell was changed in **R** 2.6.0 to
agree with that used by Friendly (2000).

References
~~~~~~~~~~

Snee, R. D. (1974) Graphical display of two-way contingency tables. *The
American Statistician*, **28**, 9–12.

Friendly, M. (1992a) Graphical methods for categorical data. *SAS User
Group International Conference Proceedings*, **17**, 190–200.
`http://www.math.yorku.ca/SCS/sugi/sugi17-paper.html <http://www.math.yorku.ca/SCS/sugi/sugi17-paper.html>`_

Friendly, M. (1992b) Mosaic displays for loglinear models. *Proceedings
of the Statistical Graphics Section*, American Statistical Association,
pp. 61–68.
`http://www.math.yorku.ca/SCS/Papers/asa92.html <http://www.math.yorku.ca/SCS/Papers/asa92.html>`_

Friendly, M. (2000) *Visualizing Categorical Data.* SAS Institute, ISBN
1-58025-660-0.

See Also
~~~~~~~~

``chisq.test``, ``loglin``, ``mosaicplot``

Examples
~~~~~~~~

::

    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")

