-------- Original Message --------
Subject: Discriminant analysis
Date: Thu, 18 Dec 2008 09:38:39 -0800 (PST)
From: Sarah Degroot <[email protected]>
To: <[email protected]>
I'm having a problem with discriminant analysis. I am using SPSS 15.0.
With my ln-transformed or raw corolla truss data, I get correct original
classifications of 96.0 to 100%. Cross-validated classification is 0.0
to 2.7% correct. Random groups of the same data gives 54.7% correct
originally and 20.0% correct cross-validated (which makes sense given
that I am trying to discriminate 5 groups).
It seems that there is some signal in the data, otherwise I'd think the
original classification for the random groups would be higher. But I am
very puzzled why the cross-validated classification of the real groups
is so low, at or near 0% correct, i.e. worse than random. It's like
something is forcefully insisting on the wrong answer...
Any idea why the cross-validated classifications are so poor?
Thank you,
sarah.degroot at cgu.edu
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