Hi, thank you for reading this message. I have the following problems in
getting the "correct" CRIMCOORD transformation of categorical variables
in QUEST decision tree algorithm. Your help will be greatly appreciated.
Q1: In Loh & Shih's paper (Split Selection Models for Classification
Trees, Statistica Sinica, 1997, vol 7, p815-840), they mentioned about
the mapping from categorical variable to ordered variable via CRIMCOORD.
But, their explanation, in particular, step 5 of algorithm 2 is not
clear. For example, they wrote "Perform a singular value decomposition
of the matrix GFU and let a (vector) be the eigenvector (of what?)
associated with the largest eigenvalue" in step 5. Does this mean
a(vector) is the eigenvector of transpose(GFU)*GFU?
Q2.
I tried to verify the data sets in Table 1. Data set I-III are OK. But,
the result for data set IV seems to be incorrect. Could any one of you
help me verify that?
Thank you very much for your help !!
David
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