calculate Chi-Square test

dicty has asked for the wisdom of the Perl Monks concerning the following question:

How to calculate Chi-Square test P-value with Perl? Any example? My input is the value X to evaluate the distribution and the number of the degrees of freedom.

Thanks!

Dicty

Comment on calculate Chi-Square test

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Re: calculate Chi-Square test by blue_cowdawg (Monsignor) on Feb 05, 2013 at 20:37 UTC
Take a look at Statistics::ChiSquare. If you are being asked to write this from scratch by your boss, professor or whoever check out: http://en.wikipedia.org/wiki/Chi-squared_test. Peter L. Berghold -- Unix Professional Peter -at- Berghold -dot- Net; AOL IM redcowdawg Yahoo IM: blue_cowdawg	[reply]
Re^2: calculate Chi-Square test by shagbark (Acolyte) on Aug 27, 2013 at 19:01 UTC
Statistics::ChiSquared is not a suitable package except for preliminary investigation, as it returns a text string which you have to parse the numbers out of, but more importantly as it doesn't return the correct numbers, but rounds everything off to the nearest 5% (and appears to have some special love of 30% and 70%). If every mathematical package returned a text string explaining the result rather than the result, because they don't trust you to interpret the result correctly, using Perl for math would be hell. Note the documentation says "use Statistics::Chisquare", but correct usage is "use Statistics::ChiSquare".	[reply]
Re^2: calculate Chi-Square test by Mr. Muskrat (Canon) on Feb 16, 2013 at 18:22 UTC
Good bosses don't ask you to work on a solved problem. :)	[reply]
Re^3: calculate Chi-Square test by blue_cowdawg (Monsignor) on Feb 18, 2013 at 15:51 UTC
Emphasis on the word "good." :-) Peter L. Berghold -- Unix Professional Peter -at- Berghold -dot- Net; AOL IM redcowdawg Yahoo IM: blue_cowdawg	[reply]
Re: calculate Chi-Square test by moklevat (Priest) on Feb 06, 2013 at 15:02 UTC
To add to blue_cowdawg's advice, if you need to roll your own, what you are seeking is the probability density function of the chi-squared distribution, which is given here where x is the chi-square value and k is the number of degrees of freedom, and you will need to include values from the Gamma function, which has a closed form solution for half-integer value (i.e. k/2).	[reply]

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