ERROR for proc ttest

[michellel]

Hi,

I have a question for  my t-test code listed below. After I ran my code, I got an error message as below. I checked the variable flag for class statement. It is 2-category variable. Could anyone give me some hint? Thanks so much!

proc ttest data=mydata;

var score;

class flag;

run;

ERROR: N, MEAN, or STD value occurs twice in class or by group.

[WarrenKuhfeld]

Run proc print and proc contents on your data set.  Look at the results. Is it a TYPE=SUMMARY data set (or some other special type)?  Does it have the right stuff ?  

proc means data=sashelp.class;
   var age;
   class sex;
   output out=m;
run;   

proc print; run;
proc contents varnum;  run;

proc ttest data=m;
var age;
class sex;
run;