Paired t test practical

In this practical we are going to investigate how to perform a paired t-test using SPSS. A paired t-test is used when we have two continuous variables measured for all observations in a dataset and we want to test if the means of these variables are different. The test assumes that both the variables are normally distributed. To run a single test in SPSS requires that your dataset has two separate columns containing the two variables to be tested. In this situation we could perform a standard 2 sample t-test by reshaping the two variables into one long variable with an accompanying indicator column that defines which original variable each observation refers to but this would be a less efficient test as it does not take account of the paired nature of the data.