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st: RE: sort of standardization
From
"Nick Cox" <[email protected]>
To
"Statalist" <[email protected]>
Subject
st: RE: sort of standardization
Date
Wed, 12 May 2010 20:04:39 +0100
Several answers to this all I think omitted one point about PCA.
Standardisation in the sense of (value - mean) / sd is unnecessary before PCA because you only need ask for a PCA based on a correlation matrix.
However, you're not guaranteed the same result with (value - min) / (max - min) OR value / (max - min).
Nick
[email protected]
From: [email protected] [mailto:[email protected]] On Behalf Of Ginevra Biino
I have to standardize many variables (in order to run PCA).
Besides generating the n corresponding std(varname) vars, which I have already done, I also want to generate n new variables obtained dividing each variable by its range. Can anybody help me?
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