ttest for Independent
Samples  Arrangement of Data
In order to perform the ttest
for independent samples, one independent (grouping) variable (e.g., Gender) and at least one dependent variable
(e.g., a test score) are required. The means of the dependent variable
will be compared between selected groups based on the specified values
(grouping codes, e.g., male and
female) of the independent variable.
The following data set can be analyzed with a ttest
comparing the average WCC score
in males and females:

GENDER 
WCC 
case 1 
male 
111 
case 2 
male 
110 
case 3 
male 
109 
case 4 
female 
102 
case 5 
female 
104 

mean WCC in males = 110
mean WCC in females = 103 
If you specified a list of dependent variables, then a series of ttests will be performed (one for
each dependent variable).