data guyer;
  * From Fox, Applied Regression Analysis. ;
  * Fox and Guyer's Experiment on Anonymity and Cooperation ;
  * Source: J. Fox and M. Guyer (1978), "'Public' choice and cooperation ;
  * in n-person prisoner's dilemma." Journal of Conflict Resolution 22:469-481. ;
  length pubanon sex $ 1;
  input group numcoop pubanon sex ;
  * group    "Group Number" ;
  * numcoop  "Number of Cooperative Choices" ;
  * pubanon  "Choice Public or Anonymous" ;
  * sex      "Sex" ;
cards;
 1 49 P M
 2 64 P M
 3 37 P M
 4 52 P M
 5 68 P M
 6 54 P F
 7 61 P F
 8 79 P F
 9 64 P F
10 29 P F
11 27 A M
12 58 A M
13 52 A M
14 41 A M
15 30 A M
16 40 A F
17 39 A F
18 44 A F
19 34 A F
20 44 A F
;
run;

proc means ;
run;

proc freq ;
 tables pubanon sex;
run;