Which are which.....high probability running formations & passing formations
 

Can someone tell me what formations the computer is likely to run out of and which ones they are likely to pass out of.

Just look at what formation your own scout recommends on gameplans for running and passing situations. Since the logic for your scout and the AI are the same, you can get a pretty good general idea of what are running formations and what are passing formation. Then look at your opponent's starter quarterback to see what formations he knows to narrow it down further.

Check out a default game plan. Go to the formation usage pages for Extreme Passing through Extreme Running, that should give a pretty good idea.