70% or 80% is pretty good odds, you get a lot worse odds with other things in life.
Research is always nice to have on your cv, but there are people who get in with no research at all.
You have to have something on your cv that stands out. If you don't have any research, you should have high scores. If you don't have high scores, you should have excellent letters of recommendation. Ideally, you have a little bit of everything, so that if they are evaluating you with a point system, you have at least a point in every category, but you don't need to be the "complete" package, because few people really are.