Hi,   I have experience in SAS but I'm having trouble using SAS EM. I have a few questions:   1. How is purity measured/ranked? 2. Is the purity of a node based on the training data or the validation data?  3. Why is the purity of a node indicated by training/validation (answer to number 2) data? 4. How do you know (by looking at a tree), which nodes are the purist?   Thanks ... View more