I am running a CHAID classification tree on SPSS to classify my data set. I have a couple independent variables including categorical and continuous ones. For continuous variables, I've noticed that SPSS (and other software as well) technically binned the continuous variables into groups having similar observations. My question is why it is necessary for the groups to have similar observations?
To make it more sense, I am thinking of using Jenks algorithm to categorize my continuous variables into categories as inputs to the CHAID tree. Do you think such approach is good?
Also, could you tell me how to determine the number of parent and child nodes as well as the tree depth?