options nocenter ls=130 ps=600;

data a;
   infile 'ash.dat' missover;
   input cow week stage age trt herd milk fat prot scc lscore
      clin milkloss x14-x23;
   if fat=0 then fat=.;
   if prot=0 then prot=.;
   if scc=0 then scc=.;
   if lscore=0 then lscore=.;

data b;
   infile 'marsh.dat' missover;
   input cow week stage age trt herd milk fat prot scc lscore
      clin milkloss x14-x23;
   if fat=0 then fat=.;
   if prot=0 then prot=.;
   if scc=0 then scc=.;
   if lscore=0 then lscore=.;

data all; set a b;
                        season = 'w ';	/* 4 */
   if  5<=week<=16 then season = 'sp';	/* 1 */
   if 17<=week<=29 then season = 'sm';	/* 2 */
   if 30<=week<=41 then season = 'f ';	/* 3 */
   lscore= ((log(scc/100)) / (log(2))) + 3;

proc sort; by age herd trt cow season;
proc means noprint; by age herd trt cow season;
   var milk--lscore stage;
   output out = means mean = milk fat prot scc lscore stage;
proc print;
   var age herd trt cow season milk fat prot scc lscore stage;