options nodate pagesize=54 linesize=80;

/* Read in the input file   */

data ex0502;
* infile '../../../data/biostat/ex0502.dat';
infile 'C:\biostat\data\ex0502.dat';
input pipesmk lipcncr pipesmk_r lipcncr_r;
run;

/* Obtain crosstabs and relative risk / odds ratios based on reversed pipesmk and lipcncr (SAS default is to model
the probability in the "lowest" category) */

proc freq;
table pipesmk_r*lipcncr_r / relrisk;
run;

quit;