Two-Group T Test
A two group T test asks whether the mean of a column for one group is significantly different than the mean of that column for another group.
Suppose we wanted to know if there was a difference between males and females as to how they did on Test 4. The following example would do a two group t-test to see if there is a difference between the means of the two groups.
MTB> TWOT 95 'TEST4' , 'SEX'
The TWOT command in MINITAB assumes that the data values will be in one column, and the codes containing group codes will be in another column.
TWOSAMPLE T FOR TEST4
sex N MEAN STDEV SE MEAN
1 11 80.4 13.3 4.01
2 9 81.56 8.11 2.70
95 PCT CI FOR MU 1 - MU 2: (-11.45,9.070)
TTEST MU 1 = MU 2 (VS NE): T= -0.25 P=0.81 DF= 16
The p value for the test is .81. Since this is not less than .05, we cannot conclude that there was any difference between how males and females did on test 4.