On 09/04/2012 03:23 PM, Lars Buitinck wrote: > 2012/9/4 <[email protected]>: >> Date: Tue, 04 Sep 2012 14:49:44 +0100 >> From: Andreas Mueller <[email protected]> >> Subject: [Scikit-learn-general] p values of exactly zero in chi2 >> To: [email protected] >> Message-ID: <[email protected]> >> Content-Type: text/plain; charset=ISO-8859-1; format=flowed >> >> Hi everybody. >> I'm pretty new to feature selection stuff and I tried to use the chi2 >> selection. >> I got a pvalue of exactly zero on one of the features and one of e-250 >> on another one. >> That seems a bit fishy, in particular as they don't seem to correlate >> very strongly. >> Maybe I misunderstood something. >> Any hints? > What did the input look like? chi2 expects frequencies, i.e. strictly > non-negative feature values. > The inputs were non-negative, but some >1.
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