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

Data originally from Oehlert, G.~W. (1994).  ``Isolating one-cell
interactions.'' {\em Technometrics\/}~{\em 36}, 403--408.

Replicated factorial with four factors, each at two levels.
Columns are factor levels (A, B, C, D) and response.