Compare Canada to Vermont, NH, Wisconsin, Montana and Idaho and see if your difference still holds. USA is a big place, with very different cultures and outcomes. Once you compare Canada to states that are culturally like Canada, your university hypothesis doesn't look to be correct.
Can you provide more sources that show Police education by state? While I don't disagree with the premise you are suggesting in and of itself, the link you've provided is entirely insufficient to make the calculations about police education and per capita police violence rate
I found [0], which in Appendix F has a state-by-state breakdown for only some states. Cross referencing it with your data source is useless, all the top states for per-capita police killings have their data omitted from that table.
https://worldpopulationreview.com/state-rankings/police-kill...