I'm running an analysis on a dataset that captures the test-scores of students before and after they took a class (control group). I also have the same data on an experimental group, test-scores of students before and after they took a class.
I already ran paired t-tests to determine the significance of the mean scores for pre- and post-tests for each group. However, I'd like to look at the difference in percentage change between the two groups. For example, (% change in experimental group) minus (% change in control group), or even the raw score difference of the same note. Is there a test I can run to determine if the difference in differences is statistically significant?
Thank you so much!