Using the package “Tree”


Predicting whether the organization’s purpose is religious

Data needs to be factor to classify, so I restructure the outcome variable. Set up seperate data frame with the training data.

train <- sample(1:nrow(dat2), 1200)

dat2$religiousorg <- ifelse(dat2$Orgpurposereligious==1, "religious", "ungodly")
dat2$religiousorg <- as.factor(dat2$religiousorg)

train.dat <- dat2[(dat2$list %in% train), ]

-Orgpurposereligious prevents use of the outcome variable in a different form for prediction. We can see the tree that is formed with labels.

tree.religion = tree(religiousorg~.-Orgpurposereligious, data=train.dat)

text(tree.religion, pretty=0, cex=.5)

How well does it classify? We can see how the test data does with the training model.

tree.pred = predict(tree.religion, dat2[-train,], type="class")
with(dat2[-train,], table(tree.pred, religiousorg))
##            religiousorg
## tree.pred   religious ungodly
##   religious       220      84
##   ungodly         195    2579