t-test for Independent Samples - Arrangement of Data
In order to perform the t-test for independent samples, one independent (grouping) variable (example, Gender) and at least one dependent variable (example, a test score) are required.
The means of the dependent variable is compared between selected groups based on the specified values (grouping codes, example, male and female) of the independent variable. The following data set can be analyzed with a t-test 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 t-tests is performed (one for each dependent variable).