kyphosis                package:rpart                R Documentation

Data on Children who have had Corrective Spinal Surgery

Description:

     The 'kyphosis' data frame has 81 rows and 4 columns. representing
     data on children who have had corrective spinal surgery

Usage:

     data(kyphosis)

Format:

     This data frame contains the following columns:

     'Kyphosis' a factor with levels 'absent'  'present' indicating if
          a kyphosis (a type of deformation) was present after the
          operation.

     'Age' in months

     'Number' the number of vertebrae involved 

     'Start' the number of the first (topmost) vertebra operated on.

Source:

     John M. Chambers and Trevor J. Hastie eds. (1992) _Statistical
     Models in S_, Wadsworth and Brooks/Cole, Pacific Grove, CA 1992.

Examples:

     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)

