Continuous variable selection & Splitting in Regression Tree

non-linear
regression
cart

#1

In a regression tree, how is a root determined out of a bunch of continuous predictors?
What logic is used to split the continuous & categorical variables in a regression tree?


#2

This is based on reduction in variance, Kindly refer to
http://www.stat.cmu.edu/~cshalizi/350-2006/lecture-10.pdf