has part denotes has_specified_input has_specified_output achieves_planned_objective has value statistical hypothesis test objective data transformation test of association between categorical variables false positive rate number of degrees of freedom Cochran-Mantel-Haenzel test for repeated tests of independence true 1 2 2 2 1 Orlaith Burke Alejandra Gonzalez-Beltran CHM test Cochran-Mantel-Haenzel test for repeated tests of independence is a statitiscal test which allows the comparison of two groups on a dichotomous/categorical response. It is used when the effect of the explanatory variable on the response variable is influenced by covariates that can be controlled. It is often used in observational studies where random assignment of subjects to different treatments cannot be controlled, but influencing covariates can. The null hypothesis is that the two nominal variables that are tested within each repetition are independent of each other. So there are 3 variables to consider: two categorical variables to be tested for independence of each other, and the third variable identifies the repeats. Mantel–Haenszel test Philippe Rocca-Serra STATO adapted from wikipedia (http://en.wikipedia.org/wiki/Cochran–Mantel–Haenszel_statistics) and from the Handbook of Biological Statistics (http://udel.edu/~mcdonald/statcmh.html) cmh.test(x,y,z) dichotomous variable association between categorical variables testing objective 2 by 2 contingency table Cochran-Armitage test for trend odds ratio homogeneity hypothesis stratum population Chi-square probability distribution categorical variable p-value ready for release