data studying;
input hours plans $;
cards;
15	S
7	S
15	S
10	S
5	S
5	S
2	S
3	S
12	S
16	S
15	S
37	S
8	S
14	S
10	S
18	S
3	S
25	S
15	S
5	S
5	S
6	NS
8	NS
15	NS
6	NS
5	NS
14	NS
10	NS
10	NS
12	NS
5	NS
;
proc print data=studying;
run;

proc ttest data=studying;
var hours;
class plans;
run;