In this practical we are going to investigate how to perform an independent samples t-test. This test is used when we have an interval or ratio level variable measured for two separate, or independent, groups of cases and we want to test if the mean of this dependent variable is different in the two groups. The test assumes that the dependent variable is normally distributed in both groups. To run a single test in SPSS requires that your dataset has one column containing the dependent variable to be tested and another column of the same length containing an indicator for which group the case belongs to.