those are some program of the sas system .and very useful when doing the statistic working .

				title'两个正态总体均值的假设检验';
				data ex ;
				input leibie$ x@@;
				cards;
				a 8.6 a 8.7 a 5.6 a 9.3 a 8.4 a 9.3 a 7.5 a 7.9
				b 8.0 b 7.9 b 5.8 b 9.1 b 7.7 b 8.2 b 7.4 b 6.6
				;
				proc ttest;
				class leibie;var x;run;