proc format;
value yes_no 0 = 'No'
             1 ='Yes';
run;

data Acc_hist;
  Input accpty drkprob prv_acc;
Format accpty drkprob prv_acc yes_no.;
datalines;
1 0 1
1 1 1
1 1 1
1 0 0
1 1 1
0 0 1
0 1 0
0 1 0
0 0 1
0 0 0
0 1 0
0 0 1
0 1 0
0 0 0
0 0 0
1 1 0
1 0 1
1 1 1
1 1 1
1 0 1
1 1 1
1 1 0
1 0 1
1 1 0
1 1 1
0 1 1
0 1 1
0 0 1
0 0 1
0 1 0
0 0 0
0 0 1
0 1 0
0 0 0
0 0 0
1 1 1
1 1 0
1 0 1
1 1 1
1 1 0
1 1 1
1 1 0
1 1 1
1 1 1
1 1 1
;


proc logistic data= Acc_hist descending;
  Title 'predicting accidents using drinking prob. & accident history';
model accpty = drkprob prv_acc/
               selection = forward
               ctable pprob = (0 to 1 by 0.1)
               lackfit
               risklimits;

run;


proc freq data=Acc_hist;
    Title 'odds ratio between past yr accidents and drinking prob. &
past yr accidents and its history';
tables  drkprob*accpty  prv_acc*accpty / chisq cmh;
run;