Modeling and Multivariate Methods - SAS

Chapter 13 Recursively Partitioning Data 323
Partition Method
Stopping Rules
If validation is not used, the platform is purely interactive. Keep pushing the Split button until the result is
satisfactory. Without cross-validation enabled, Partition is an exploratory platform intended to help you
investigate relationships interactively.
When cross-validation is used, the user has the option to perform automatic splitting. This allows for
repeated splitting without having to repeatedly click the Split button. See “Automatic Splitting” on page 328
for details on the stopping rule.
Categorical Responses
When the response is categorical, the report differs in several ways (see Figure 13.7). The differences are
described here, using the Car Poll.jmp data table:
• The G 2 statistic is given instead of the Mean and Std Dev at the top of each leaf, and instead of SS in the
Candidates report. See “Statistical Details” on page 348 for more information about G 2 .
• The Rate statistic gives the proportion of observations in the leaf that are in each response level. The
colored bars represent those proportions.
• The Prob statistic is the predicted value (a probability) for each response level. The Y axis of the plot is
divided into sections corresponding to the predicted probabilities of the response levels for each leaf.
The predicted probabilities always sum to one across the response levels. Random jitter is added to
points in the X and Y direction in a leaf. See “Statistical Details” on page 348 for more information
about the Prob statistic.
• For the plot, the vertical position is random.
• The Color Points button appears. This colors the points on the plot according to the response levels.