A data set from Oehlert (2000) \emph{A First Course in Design and
Analysis of Experiments}, New York: W. H. Freeman.

Data originally from Swanlund, D.~J., M.~R. N'Diaye, K.~J. Loseth,
J.~L. Pryor, and B.~G. Crabo (1995).  ``Diverse testicular responses
to exogenous growth hormone and follicle-stimulating hormone in
prepubertal boars. {\em Biology of Reproduction\/}~{\em 53}, 749--757.

Columns are litter, GH (absent or present), FSH (absent
or present), and response (in meters)