tigao0426 发表于 2013-2-13 09:28
下面是SAS的code
if duration > 3 then d=1; else d=0; (分成两组, d=1 and d=0)
运行出来了
结果如下 The TTEST Procedure
Variable: Interval
d N Mean Std Dev Std Err Minimum Maximum
0 105 59.3714 7.0605 0.6890 47.0000 80.0000
1 159 87.4932 17.5419 1.3912 1.8000 113.0
Diff (1-2) -28.1218 14.3303 1.8020
d Method Mean 95% CL Mean Std Dev 95% CL Std Dev
0 59.3714 58.0050 60.7378 7.0605 6.2176 8.1700
1 87.4932 84.7455 90.2409 17.5419 15.8025 19.7148
Diff (1-2) Pooled -28.1218 -31.6701 -24.5734 14.3303 13.2013 15.6721
Diff (1-2) Satterthwaite -28.1218 -31.1810 -25.0625
Method Variances DF t Value Pr > |t|
Pooled Equal 262 -15.61 <.0001
Satterthwaite Unequal 224.5 -18.11 <.0001
Equality of Variances
Method Num DF Den DF F Value Pr > F
Folded F 158 104 6.17 <.0001
说明两组之间没有差异?仅仅0.0001就看这个吗?