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| frets   | R Documentation   |
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Head Dimensions in Brothers
---------------------------

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

The ``frets`` data frame has 25 rows and 4 columns.

The data consist of measurements of the length and breadth of the heads
of pairs of adult brothers in 25 randomly sampled families. All
measurements are expressed in millimetres.

Usage
~~~~~

::

    frets

Format
~~~~~~

This data frame contains the following columns:

``l1``
    The head length of the eldest son.

``b1``
    The head breadth of the eldest son.

``l2``
    The head length of the second son.

``b2``
    The head breadth of the second son.

Source
~~~~~~

The data were obtained from

Frets, G.P. (1921) Heredity of head form in man. *Genetica*, **3**, 193.

References
~~~~~~~~~~

Davison, A.C. and Hinkley, D.V. (1997) *Bootstrap Methods and Their
Application*. Cambridge University Press.

Whittaker, J. (1990) *Graphical Models in Applied Multivariate
Statistics*. John Wiley.
