where the adjusted p-value is calculated in a complex manner that takes into account the number of different ways splits can occur. This calculation is very fair compared to the unadjusted p-value, which favors Xs with many levels, and the Bonferroni p-value, which favors Xs with small numbers of levels. Details about the method are discussed in Sall (2002).
SStest = SSparent - (SSright + SSleft) where SS in a node is just s2(n - 1).
For categorical responses, the G2 (likelihood-ratio chi-square) appears in the report. This is actually twice the [natural log] entropy or twice the change in the entropy. Entropy is Σ -log(p) for each observation, where p is the probability attributed to the response that occurred.
A candidate G2 that has been chosen is:
G2 test = G2 parent - (G2 left + G2 right).

Help created on 9/19/2017