I know that phd programs are incredibly competitive and 4.0 students with high GREs can still get rejected, but are masters programs, say at a large public university like the university of Minnesota, as competitive? Would I likely get in with a pretty high GPA and a pretty good GRE score along with average experience? Is there any way that I could almost guarentee admission (95% chance or so of acceptance) with measurables such as GPA, math GRE, etc?
Masters are still competitive, and departments generally have a limit on how big a cohort they can handle or want - remember that grad students still take up resources, and they aren’t going to hire new faculty and staff just because they have a ton of good applicants (even if those applicants are paying)! Having a GPA and GRE scores well above the average for that department will certainly make you a “high probability” admit, but I would hate to assign an actual percentage chance.
Are you dead set on a particular school? The suggestions for grad school are the same as the suggestions for college - apply to a couple of “reach” departments, a few “probable” departments, and a couple of “safety” departments. You seem to be focusing on a department that would almost definitely qualify as a “safety”, and that is rarely a good aim point. Although having said that, some departments at large public universities can be quite highly regarded and selective, so perhaps you are aiming higher than it appears…