How to perform two-sample t-test with Minitab? I am trying to do a few tests in Minitab and I don't understand why they are not working out.  
First, my data in minitab has several columns: Class Name Gender Height Age, where 


*

*Class has two values {A,B};

*Name is the name of the students; 

*Gender is Female or Not female;

*Age is the age of the student. 


My questions I have to answer are as follows: 
Is the height of Class A larger than Class B?
My understanding of the question 
I should be  a 2 sample t-test of the differences of the  Height of Class A - Class B 
However, every time I try to do a two sample t-test it just compares class with height, which is silly and doesn't workout.   
How Do I get Minitab to test Class A's height against Class B's height? 
Ps.  If I am incorrect in the correct hypothesis testing method, please let me know.  
 A: I don't have Minitab so I can't show you the exact syntax or GUI menu actions to perform a t-test for independent samples. However, statistical packages (e.g., R, Stata) generally provide commands to perform a t-test when data are organized as either


*

*two series of measurements, one for each group (usually arranged in two columns);

*all individual measurements in one column, described by group levels in another column.


With the example from Wikipedia ("weights of screws that were chosen out of a bucket"), that would mean that scheme 1 looks like: 
+-----+-----+
|A1   |A2   |
+-----+-----+
|30.02|29.89|
+-----+-----+
|29.99|29.93|
+-----+-----+
|30.11|29.72|
+-----+-----+
|29.97|29.98|
+-----+-----+
|30.01|30.02|
+-----+-----+
|29.99|29.98|
+-----+-----+

while for scheme 2 we would arrange data as follows:
+-----+-----+
|30.02|A1   |
+-----+-----+
|29.99|A1   |
+-----+-----+
|30.11|A1   |
+-----+-----+
|29.97|A1   |
+-----+-----+
|30.01|A1   |
+-----+-----+
|29.99|A1   |
+-----+-----+
|29.89|A2   |
+-----+-----+
|29.93|A2   |
+-----+-----+
|29.72|A2   |
+-----+-----+
|29.98|A2   |
+-----+-----+
|30.02|A2   |
+-----+-----+
|29.98|A2   |
+-----+-----+

As explained on this short tutorial on Minitab 2-Sample-t-test, any scheme can be used by filling out the correct option in the 2-Sample-t dialog box. In your case, that means selecting Height as Samples and Class as Subscripts, with Samples arranged in one column. After running your t-test, you may want to check usual assumptions (normality and homogeneity of variance).
A: Two series of measurements can be given in two separate columns as well in Minitab.
Considering the example in Wiki


*

*Enter two samples in two columns

*Go to Stat Menu -> Basic statistics -> 2-sample-t-test


And select "samples in different columns".
You can choose "sample is one column" if you have arranged measurements in one column.

Click "OK". 
