7 Independent T-Tests
This activity introduces the independent t-test – a powerful test to use when you are comparing two groups or conditions. There are two variants of the t-test:
paired samples t-tests.
The independent t-test is used when you have two groups of individuals or cases. For example:
male versus female;
experimental versus control group.
Data files are set up differently according to which t-test is chosen. In addition there are separate menus in SPSS for each type of t-test. Finally, each t-test will produce different outputs.
For an independent t-test the data file should have at least two columns – one for the independent variable and one for the dependent variable.
Warning – these tutorials sometimes don’t display properly in Google Chrome. This is a common issue that occurs when Chrome’s ‘Use hardware acceleration when available’ option is switched on. This option is enabled by default, however disabling it should correct this problem. To do this, click on the three dots in the top right corner of the Chrome browser, select 'Settings’ and then ‘Advanced Settings’ at the bottom. Turn off this option underneath the ‘System’ heading, and then close down and restart Chrome. Alternatively, using a different browser should allow you to view the tutorials properly.
You can download this SPSS file from this tutorial here.