Running A T-Test in SPSS
Using SPSS for T-Test
One Sample T-Test
One sample t-tests can be used to determine if the mean of a sample is different from a particular value.
Independent Sample T-Test
When two samples are involved, the samples can come from different individuals who are not matched (the samples are independent of each other.) Or the sample can come from the same individuals (the samples are paired with each other) and the samples are not independent of each other. A third alternative is that the samples can come from different individuals who have been matched on a variable of interest; this type of sample will not be independent. The form of the t-test is slightly different for the independent samples and dependent samples types of two sample tests, and SPSS has separate procedures for performing the two types of tests.
Paired Samples T-Tests
When two samples are involved and the values for each sample are collected from the same individuals (that is, each individual gives us two values, one for each of the two groups), or the samples come from matched pairs of individuals then a paired-samples t-test may be an appropriate statistic to use.