[Feature Request] X² test for 2×2 contingency tables

[omaus]

Is your feature request related to a problem? Please describe.
An often used variant of the X² (Chi-squared) test is that for 2×2 contingency tables (aka Cochran-Mantel-Haenszel test). Since the original X² test is already implemented, a version for 2×2 contingency tables can easily be implemented.

Describe the solution you'd like
Implement it.

Describe alternatives you've considered
Always write it yourself with the already existing X² test.

Additional context
https://en.wikipedia.org/wiki/Cochran%E2%80%93Mantel%E2%80%93Haenszel_statistics (eng)
https://de.wikipedia.org/wiki/Chi-Quadrat-Test#Vierfeldertest (ger)

[github-actions]

🤖 This is an automated response from Repo Assist.

This is directly related to PR #367, which I recently opened, that adds computeWithYates and computeWithWilliams to the ChiSquareTest module.

Yates' continuity correction is specifically recommended for 2×2 contingency tables when expected cell counts are small, to reduce the over-rejection of H0. PR #367 adds:

// Chi-squared goodness-of-fit with Yates correction
ChiSquareTest.computeWithYates(observed, expected)

// Chi-squared goodness-of-fit with Williams correction
ChiSquareTest.computeWithWilliams(observed, expected)

For the test of independence in a 2×2 table, the existing ChiSquareTest.testOfIndependence (via ContingencyTable) applies standard Pearson chi-squared; the Yates-corrected version from PR #367 can be applied similarly.

If this covers what you were looking for, the issue could be closed after PR #367 is merged — or a follow-up task for testOfIndependence to accept a continuityCorrection parameter could be tracked there.

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