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From Andrew Schaumberg <schaumberg.and...@gmail.com>
Subject [math] chi-squared test default deg freedom should be n-2 not n-1?
Date Sun, 23 Aug 2015 01:04:59 GMT
Dear devs,

Chi-squared test takes degrees of freedom to be one fewer than the sample
count.
https://commons.apache.org/proper/commons-math/apidocs/src-html/org/apache/commons/math3/stat/inference/ChiSquareTest.html#line.154

Should be two fewer, right?
http://courses.wcupa.edu/rbove/Berenson/10th%20ed%20CD-ROM%20topics/section12_5.pdf

d.f. = k - p - 1
k is sample count
p is # parameters being estimated (typically 1)

One fewer is typically for T-test, I think.

Not a statistician, thanks for your time, sorry if this is the wrong agent,
first time here,
-A

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