I have two groups (control and experimental) with 16 subjects each. Their pre-test scores are statistically different from a normal distribution so I opted to do nonparametric tests. I need to compare the learning gains of the students (post test score minus pre test score) but don't know what nonparametric test to use. I know though that if I were to use parametric tests, the ANCOVA is the test that I should use. What is ANCOVA's nonparametric test counterpart?
EDIT: Can I use Quade's test for this? This is a quasi-experimental study by the way, with the objective of determining whether a learning intervention enhance student achievement.
Thanks in advance!