EZAnalyze contains three t-test options; a one sample, paired samples, or independent samples t-test. Each is briefly described below, with a link for going directly to the help topic for each type of t-test.
One Sample T-Test - appropriate for use when you are comparing a value that is known in the population to your data. For example, if you want to know how students in your school compare to students in the US on the SAT, you would use this test because we know the national average SAT score is 1000 (or perhaps 1500 if you use all three sections).
Paired Samples T-Test - use this when you want to compare data that are in two columns from the same person. This is a "repeated measures" t-test because appropriate use requires that the same person contributed scores to both measures. An excellent example of this is to see if there is a difference between pretest scores and posttest scores after some kind of intervention.
Independent Samples T-Test - the most common type of t-test, this is appropriate for use when you want to see how two different groups performed on some dependent measure. For example, if you want to see if boys and girls have significantly different attendance rates at your school, you would use the independent samples t-test to get your answer.