Modeling and Multivariate Methods - SAS

Chapter 13 Recursively Partitioning Data 321
Partition Method
Figure 13.5 First Split
The original 506 observations are now split into two parts:
• A left leaf, corresponding to rooms < 6.943, has 430 observations.
• A right leaf, corresponding to rooms ≥ 6.943, has 76 observations.
For the left leaf, the next split would happen on the column lstat, which has a SS of 7,311.85. For the right
leaf, the next split would happen on the column rooms, which has a SS of 3,060.95. Since the SS for the left
leaf is higher, using the Split button again will produce a split on the left leaf, on the column lstat.
Click the Split button to make the next split. See Figure 13.6.