options formdlim = '-';

data brain;
  infile '/home/pdixon/WWW/stat401/data/brain.txt';
  input gest brain body litter species $;
  
  loggest = log(gest);
  logbrain = log(brain);
  logbody = log(body);
  loglitter = log(litter);
  
proc glm;
   model logbrain = logbody loglitter;
   title 'Regression of log brain size on log body and log litter';
   
proc glm;
   model logbrain = logbody loglitter loggest;
   title 'Regression of log brain size on log body, log litter and log gest';
run;
         
/* could also use proc reg; */

proc reg;
   model logbrain = logbody loglitter;
   title 'Regression of log brain size on log body and log litter';
run;