ND Stats/team rankings
Maybe this link would be helpful. It's a very good team offensively and defensively. They didn't play great teams but played consistently well all year except for one early season game. Because of that early loss and their mediocre schedule, ND really didn't get much attention and kind of snuck up on people. The consistency is what worries me about them. They aren't going to play a bad game, they aren't going to give anything away. They play aggressive, they have an excellent QB and they don't give stuff away. They're very well coached and they have first rate athletes.
PSU can win this game, they have the athletes and the coaching, they have leadership, they have toughness. But somehow, magically they need to eliminate all the problems that have held them back so far in the playoffs -- inconsistent QB play, dropped passes, defensive PFs, offensive procedure penalties, and coaching brain farts like calling gadget plays when they can run the ball at will. Can PSU clean up ALL that stuff in one week?
What the Vegas line is saying is that PSU can win but they don't expect PSU to win, and that is understandable. PSU has gotten this far without really playing a four-quarter game. They're in the semifinals largely because they haven't played a great team yet. Notre Dame is the best team PSU has seen other than Ohio State.