-------- Original Message --------
Subject: regression of Procrustes coordinates on classifiers
Date: Fri, 27 Feb 2009 05:55:11 -0800 (PST)
From: Louis Boell <[email protected]>
To: <[email protected]>
Dear colleagues,
I wish to investigate how strongly the fact that a sample of specimens
belongs to a given class, say, samples from desert vs samples from
forest, influences the Mahalanobis distances between my samples. This
amounts to "correcting" for the desert vs forest "factor"
and checking how much smaller the Mahalanobis distances between desert
and forest samples get when calculated from the residuals of the
"correction".
I have about 10 samples per class (each sample in itself consisting of
enough specimens given the number of landmarks) from each class).
In this situation, I tried "correction" by using a dummy-coded
regression (desert=1, forest=2) of Procrustes coordinates on my factor
in MorphoJ. The results are appealing. Now I know that for a
noncontinoous independent variable, you´d prefer to use logistic
regression instead of simple regression, because the fit will be more
appropriate in this case.
My question is: is there a statistical reason not to use this procedure?
Or caution about the interpretation of the results?
I´d be grateful for any advice
Best wishes
Louis
Louis Boell
MPI für Evolutionsbiologie
August-Thienemannstr.2
24306 Plön
[email protected]
[email protected]
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