Independent Samples T-Test Use Case

For an example of this test's usage, see the below sample data from a puppy training program that measures the skills of the puppies before they enter the program and after they leave the program.

Suppose that Rachel argues that Jenny gets assigned more talented puppies. We could test this assumption by running an independent sample t-test on the Score Before Training column, and grouping by the Trainer Name Column. In this case, the null hypothesis is that the mean Score Before Training for Rachel's puppies is not statistically lower than Jenny's puppies. We would reject the null hypothesis if the Lower One Tailed p-value is less than 0.05.

The model assumes that a difference in the mean score of the dependent variable is found because of the influence of the independent variable. Thus, the independent sample t-test is an analysis of dependence. It is one of the most widely used statistical tests. (source)

Using the example of the puppy training program, are Jenny's puppies better at the skills challenge before or after training than Rachel's? In that case, we would select both the Score Before Training column and the Score After Training column for the Columns to Test parameter. We select "Trainer Name" as the Column to Group By. Because this test can only be computed on two groups and there may be more than two values in the Group By column (in this case, if there were more than two trainers), we have to specify which two groups to run the test on. We fill in the two values in the group by column in the First Group Value parameter and the Second Group Value parameter. In this case we would enter "Rachel" and "Jenny".