Response to leprosy treatment. In 1954, the prominent statistician W. G. Cochran (1909–1980) published an important article on the analysis of cross-tabulated counts. In this article, techniques were illustrated with an example from a study on the treatment of leprosy.

Table 18.10 lists the cross-tabulated results. The row variable in this table classifies patients according to their initial degree of skin damage. The column variable classifies response to therapy according to five levels of improvement. Address whether patients with high levels of skin damage progressed differently than those with low levels of skin damage by calculating the conditional percents of improvement in the two groups. Comment on these findings.