Author here -- thanks for the comment! I also would agree that GPA isn't necessarily the right metric here. The reason I chose all these factors to compare to grades is because I feel that's the stereotype those in academia (students and professors alike) have, that somehow a lot of sleeping and no fun and studying a lot leads to good grades. I was curious whether that was true.

Even though there's a huge negative correlation between activities and grades in my data, doesn't mean that I would sacrifice the time I spent on activities just so that I could get the "better grade". My jobs and student orgs made my experience, and I would still spend time on it again even if my grades suffer.

That sounds like a really good project! Would love to compare notes and read about your results if you make it public somewhere!