#
# EPage 374
#
# Written by:
# -- 
# John L. Weatherwax                2009-04-21
# 
# email: wax@alum.mit.edu
# 
# Please send comments and especially bug reports to the
# above email address.
# 
#-----

save_plots = F

library(DAAG)
library(rpart)

set.seed(29)

head.injury$clinically.important.brain.injury = as.factor(head.injury$clinically.important.brain.injury)

# Part (a):
# 
m = rpart( clinically.important.brain.injury ~ ., data=head.injury, method="class" )

# Part (b-c):
#
if( save_plots ){ postscript("../../WriteUp/Graphics/Chapter11/prob_1_plot.eps", onefile=FALSE, horizontal=FALSE) }

m = rpart( clinically.important.brain.injury ~ ., data=head.injury, method="class", cp=0.0001 )
plotcp(m)

if( save_plots ){ dev.off() }

# Pick the tree of size 4 by pruning using that trees value of cp
#
m = prune( m, cp=0.022 )

# Display the tree: 
plot(m); text(m, digits=3)