Hello everyone,
I had a question about taking an anti-requisite course. This is my situation:

I took a course in my department that I did poorly in. I know that if you retake a course, your two marks on how you did on that course are averaged on your transcript.

I would like to take a course offered by another faculty that is an anti-requisite for the course I did poorly in. Would this be allowed? Moreover, if I were allowed to take it, how would the mark show up on my transcript? Would the mark of the anti-requisite course be averaged with the original course I took in my department?

Has anyone had a similar experience or know the university policy regarding this? Any help is greatly appreciated!

I don't think you would be allowed to take the course in the first place. There are certain circumstances where it is allowed, but it's usually if you switch programs or something and need the anti-requisite specifically. You should talk to an academic advisor.

Antireq means you can't take it. Even if you do, any marks will cancel out
http://www.mcmaster.ca/parttime/glossary.html

What do you mean by the marks will cancel out?

It won't count. SOLAR won't let you enrol even. You can't use antireqs as a workaround for patching over a bad grade. Mac doesn;t offer that. They are one of the few schools that don't even offer a true upgrade. All attempts at a course stay on your transcript and count towards your GPA.