\HeaderA{rats}{Rat data from Gail et al.}{rats}
\keyword{survival}{rats}
\keyword{datasets}{rats}
\begin{Description}\relax
48 rats were injected with a carcinogen, and then
randomized to either drug or placebo.  The number of tumors ranges
from 0 to 13; all rats were  censored at 6 months after randomization.
\end{Description}
\begin{Usage}
\begin{verbatim}rats\end{verbatim}
\end{Usage}
\begin{Format}\relax
\Tabular{ll}{
rat:& id\\
rx:& treatment,(1=drug, 0=control) \\
observation:& within rat\\
start:& entry time\\
stop:& exit time\\
status:& event status\\
}
\end{Format}
\begin{Source}\relax
MH Gail, TJ Santner, and CC Brown (1980),
An analysis of comparative carcinogenesis experiments based on
multiple times to tumor.
\emph{Biometrics} \bold{36}, 255--266.
\end{Source}

