New feature: Pearson's chi-squared test. about pingouin HOT 8 CLOSED

Hello @raphaelvallat,

Sure, I'm working on it. While researching, I think I found how the extra metrics could be explicit on the results.

The test can be performed with a few different values for lambda_, as seen here. And for each value of lambda_, there should be a different pair of χ² and p-value.

Wrapping it up, pg.chi2 could return tests for each lambda_ (not just for the Pearson's) as well as the degree of freedom and the contingency table with expected frequencies.

I'll be back soon with the Jupyter Notebook.

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Btw if you prefer to work on a PR of your own, please feel free to fork the develop branch and submit it when you're done ;-)

That'd be great. I'm just a bit busy lately, but I'm eager to participate and help :D

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Working on it and learning a lot! (arthurpaulino@41f176f)

I'll implement the tests tomorrow. Any feedback is welcome 😃

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This looks absolutely great @arthurpaulino ! Amazing job, can't wait to try it out!

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PS: you also need to add the datasets to the MANIFEST.in file, otherwise the example dataset will not be installed with pip!

Thanks!

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Hi @arthurpaulino!

Thank you for your message! I don't use this test very often, but I'd be happy to implement it in the next release (or more realistically the one after the next). It would be very helpful if you could share a Jupyter Notebook showing how you would typically do this test using Pandas + SciPy, as well as the kind of metrics / information that you would be interested in having as an output of the pg.pearson_chi2 function.

Best,
Raphael

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Alright, that took a while. It was a good learning experience for me.

I tried to keep the example as minimal and organized as possible. The result is somewhat close to a final version of what gp.chi2 would look like. The notebook link is here.

It was inspired by SciPy's implementation, which is more robust and incorporates a few more checks that would be healthy in the final version of gp.chi2, I think.

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Thank you @arthurpaulino, this looks great! I'm gonna look at that more in details this weekend, and hopefully should be able to include it in the next release or so then. (Btw if you prefer to work on a PR of your own, please feel free to fork the develop branch and submit it when you're done ;-))
Thanks!

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