options nocenter;

data a;
  input group $ hrtrate;
  cards;
P  69.169
P  68.862
A  84.738
F  99.692
A  87.231
A  84.877
P  70.169
P  64.169
P  58.692
A  80.369
A  91.754
A  87.446
A  87.785
P  69.231
P  75.985
F  91.354
A  73.277
F  83.400
F 100.877
A  84.523
F 102.154
A  77.800
A  70.877
P  86.446
P  97.538
F  89.815
F  80.277
P  85.000
F  98.200
A  90.015
F 101.062
F  76.908
A  99.046
F  97.046
P  69.538
A  75.477
A  62.646
P  70.077
F  88.015
F  81.600
F  86.985
P  72.262
P  65.446
;

proc glm;
  class group;
  model hrtrate=group / clparm;
  estimate 'Mean for Alone Group' intercept 1 group 1 0 0;
  estimate 'Mean for Friend Group' intercept 1 group 0 1 0;
  estimate 'Mean for Pet Group' intercept 1 group 0 0 1;
  estimate 'Alone Mean - Friend Mean' group 1 -1 0;
  estimate 'Alone Mean - Pet Mean' group 1 0 -1;
  estimate 'Friend Mean - Pet Mean' group 0 1 -1;
  estimate 'Alone - Not Alone' group 1 -.5 -.5;
  estimate 'Pet - No Pet' group -.5 -.5 1;
  estimate 'Friend - No Friend' group -.5 1 -.5;
run;