I'm making a decision tree in SAS EMiner. I have the data source, then the data partition node, and then a filter node before the decision tree node. When I try a decision tree interactively, some of the splits aren't making sense to me. For example I have one variable that is nominal and can be either "S" or "U". When the tree chooses this variable to split on it has two branches: "S" and "Missing Values Only". None of the entries are missing this variable. I thought that maybe the "U"'s were being filtered out by default because there were too few of them, but when I changed the "Default Filtering Method" to "None" the results did not change. I tried to change the seed number in the data partition node, but that didn't seem to help either. Does anybody know why this might be happening, or how I can fix it? Thanks,
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