chi-squared tests in python?
Robert Kern
robert.kern at gmail.com
Tue Jan 17 12:55:48 EST 2006
Matthew Vernon wrote:
> Hi,
>
> I'd like to be able to use the chi-squared test in my code. Currently,
> I can output "look up [this value] in a chi-squared table with [x]
> degrees of freedom", but that's obviously a little sub-optimal. I
> notice that numarray has a chi_square function, but that just gives
> you random numbers from a chi-squared distribution with a set number
> of degrees of freedom - not really what I want.
>
> Does there exist python code to do this? preferably something vaguely
> standard?
Yes, in Scipy.
from scipy.stats import chi2
# one-sided Chi^2 test
pval = 1 - chi2.cdf(value, dof)
http://new.scipy.org/Wiki
[This URL will be http://www.scipy.org in a week or so, I hope.]
> Matthew
> ps: given the "batteries included" philosphy, there's a remarkable dearth
> of stats in python...
I think Chi^2 tests fall distinctly in the "third-party library" category, myself.
--
Robert Kern
robert.kern at gmail.com
"In the fields of hell where the grass grows high
Are the graves of dreams allowed to die."
-- Richard Harter
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