/*************  mixed.sas *********************
Three levels of factor A, four levels of B
      Pretend both fixed
      Pretend both random
      Pretend A fixed, B random
***************************************************/

options linesize = 79;

data mixedup;
     infile 'ch19pr14.dat';
     input Y A garbage B;

/* By default, both are considered fixed */
proc glm; 
     class A B ;
     model y = a | b; 
/* Now both random */
proc glm;
     class A B ;
     model y = a | b; 
     random a b a*b; /* Have to specify interaction random too! */
     /* Are the printed F ratios correct now? */
proc glm;
     class A B ;
     model y = a | b;
     random a b a*b / test; 
     /* Are the printed F ratios correct now? */

/* Now A fixed, B random */
proc glm;
     class A B ;
     model y = a | b;
     random b a*b / test;