Which test for significance?

[mathprof]

I have 2 classes. Class #1 takes a pretest and then a posttest on a topic. Class #2, on the same topic, also takes a pretest and a posttest. However Class #2 also watches videos about the topic. I want to test whether there is a significant difference between the two classes of students as it relates to the results of the pretest and posttest scores.
What test for significance can I use?

 

[Karabiner]

Were students randomly allocated to groups? How large are the sample sizes? How exactely
was the dependent variable measured, on which scale (nominal, ordinal, or interval)? Are there
missing cases at posttest?

With kind regards

Karabiner