*! stokesdaviskoch.do Version 1.0 2004-05-07 JRC * Example from M. E. Stokes, C. S. Davis and * G. G. Koch, _Categorical Data Analysis Using The * SAS(R) System_ Second Edition. (Cary, N. Carolina: * SAS Institute, 2000), pp. 73-75, citing (on p. 67) * G. G. Koch & S. Edwards, Clinical efficacy trials * with categorical data, in _Biopharmaceutical * Statistics for Drug Development_, K. E. Pearce (ed.) * (New York: Marcel Dekker, 1988), pp. 403-51. clear set more off input str6 gender str7 treat str6 response byte count female test none 6 female test some 5 female test marked 16 female placebo none 19 female placebo some 7 female placebo marked 6 male test none 7 male test some 2 male test marked 5 male placebo none 10 male placebo some 0 male placebo marked 1 end * drop if count == 0 expand count drop count * label define Group 0 placebo 1 test encode treat, generate(trt) label(Group) label define Group 0 C 1 E, modify drop treat label variable trt "Treatment" note trt: C–Control treatment group; E–Experimental treatment group * label define Response 0 none 1 some 2 marked encode response, generate(res) label(Response) label define Response 0 None 1 Some 2 Marked, modify drop response label variable res "Response" * vanelteren res, by(trt) st(gender) display r(z)^2 * The result reported for van Elteren's test as * implemented in PROC FREQ . . . SCORES=MODRIDIT * is chi-square = 15.0041, df = 1, P = 0.0001 * (p. 75). * label define Female 0 male 1 female encode gender, generate(sex) label(Female) label define Female 0 M 1 F, modify drop gender label variable sex "Sex (is-female)" tabodds trt res, adj(sex) display chi2tail(2, r(chi2_tr)) * With a second degree of freedom assigned to the * chi-square test statistic, this gives the result * for "Statistic 3 General Association" of the PROC FREQ printout * shown on p. 75. exit