\Header{kyphosis}{Data on Children who have had Corrective Spinal Surgery}
\keyword{datasets}{kyphosis}
\begin{Description}\relax
The \code{kyphosis} data frame has 81 rows and 4 columns.
representing data on children who have had corrective spinal surgery
\end{Description}
\begin{Usage}
\begin{verbatim}
data(kyphosis)
\end{verbatim}
\end{Usage}
\begin{Format}\relax
This data frame contains the following columns:
\describe{
\item[\code{Kyphosis}] a factor with levels
\code{absent} 
\code{present}
indicating if a kyphosis (a type of deformation)
was present after the operation.

\item[\code{Age}] in months

\item[\code{Number}] the number of vertebrae involved 

\item[\code{Start}] the number of the first (topmost) vertebra operated on.

}
\end{Format}
\begin{Source}\relax
John M. Chambers and Trevor J. Hastie eds. (1992)
\emph{Statistical Models in S}, Wadsworth and Brooks/Cole,
Pacific Grove, CA 1992.
\end{Source}
\begin{Examples}
\begin{ExampleCode}
data(kyphosis)
fit <- rpart(Kyphosis ~ Age + Number + Start, data=kyphosis)
fit2 <- rpart(Kyphosis ~ Age + Number + Start, data=kyphosis,
              parms=list(prior=c(.65,.35), split='information'))
fit3 <- rpart(Kyphosis ~ Age + Number + Start, data=kyphosis,
              control=rpart.control(cp=.05))
par(mfrow=c(1,2))
plot(fit)
text(fit, use.n=TRUE)
plot(fit2)
text(fit2, use.n=TRUE)
\end{ExampleCode}
\end{Examples}

