has_specified_input has_specified_output achieves_planned_objective data transformation false positive rate 2 by 2 contingency table homogeneity test objective odds ratio Chi-square probability distribution Woolf's test 2 2 Orlaith Burke Alejandra Gonzalez-Beltran Philippe Rocca-Serra Woolf's test is a statistical test which evaluates the null hypothesis that odds ratio are the same accross all strata of population under investigation http://people.umass.edu/biep640w/pdf/4.%20%20Categorical%20Data%20Analysis%202012.pdf woolf_test(x) where x is 2 x 2 x k contingency table http://hosho.ees.hokudai.ac.jp/~kubo/Rdoc/library/vcd/html/woolf_test.html odds ratio homogeneity test homogeneity test p-value ready for release