… a statistical test of stratified selections
mh calc allows testing of association between selection and protected status, controlling for up to 18 tiers in a third variable.
mh calc computes the Mantel-Haenszel statistic, common odds ratio, and Breslow-Day test of homogeneity. Odds ratios and Fisher's exact test are computed for each tier.
Overview of Process
Data entry in mh calc is similar to entering 2x2 tables in square, with four cell values for each tier. Note: mh calc allows up to 18 tiers, but any tier with no data (i.e., all zeros) is ignored, and any tier with a zero marginal is also ignored.
For example, a tier would have a zero marginal if no women applied in that tier, or if there were no selections in that tier. Edit boxes are provided to label the tiers, and there is a dialog box to create row and column labels. The results may be printed or saved.
In the example below …
Plaintiff alleges that MH Clothing Co. failed to promote its female employees on a equal basis with their male collegues. MH Clothing claims that each store treated employees the same.
mh calc was used to analyze the relation between sex and promotion, controlling for store. The Mantel-Haenszel χ² of 5.90 yields a probability value of 0.015. Thus, there is less than a 2% chance that the association between sex and promotion is spurious. This would generally be recognized as statistically significant. Also, the Breslow-Day statistic (1.83, p=0.76) is not significant, indicating that homogeneity is not an issue.
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