/* Reading in Gosset's sleeping data */

DATA sleeping;
INPUT obs extra group;
cards;
1    0.7     1
2   -1.6     1
3   -0.2     1
4   -1.2     1
5   -0.1     1
6    3.4     1
7    3.7     1
8    0.8     1
9    0.0     1
10   2.0     1
11   1.9     2
12   0.8     2
13   1.1     2
14   0.1     2
15  -0.1     2
16   4.4     2
17   5.5     2
18   1.6     2
19   4.6     2
20   3.4     2
;
run;

PROC TTEST DATA=sleeping;
CLASS group;
VAR extra;
run;