/* Model comparison on AZT and AIDS example, used in class          */

data aids;
input race $ azt $ yes no @@; 
cases = yes + no; 
cards; 
white  y  14  93  white  n  32  81 
black  y  11  52  black  n  12  43
; 
/* M1 */
proc genmod order=data; class race  azt; 
   model yes/cases =  /  dist=bin  link=logit; 
/* M2 */
proc genmod order=data; class race  azt; 
   model yes/cases =  race/  dist=bin  link=logit; 
/* M3 */
proc genmod order=data; class race  azt; 
   model yes/cases =  azt/  dist=bin  link=logit;  
/* M4 */
proc genmod order=data; class race  azt; 
   model yes/cases =  race azt/  dist=bin  link=logit;  
/* M5, Saturated model */
proc genmod order=data; class race  azt; 
   model yes/cases =  race azt race*azt/  dist=bin  link=logit;  


/* For AZT and AIDS example on p. 111 of text.          */
/* NOTE: genmod and logistic use different sets of constraints  */
/*    so... estimates for parameters have different values    */
/*   c.f.  Table 4.5 ......................................   */

proc genmod order=data; class race  azt; 
   model yes/cases = race azt /  dist=bin  link=logit  obstats type3; 
proc logistic order=data; class race  azt; 
   model yes/cases = race azt; 
run;