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

Data originally from McCall, A.~L., W.~R. Millington, and R.~J.
Wurtman (1982).  ``Blood-brain barrier transport of caffeine:
dose-related restriction of adenine transport.'' {\em Life Sciences\/}
{\em 31}, 2709--2715.

Concentation of labeled adenine in rat brains when adenine is injected
with 0, .1, .5, 1, 5, 10, 25, or 50 mM caffeine.  Columns are treatment
number and response.