Predictions for over-under or over/under is based on expected total goals scored by both teams. Most popular betting line is 2.5, when punter bet on under 2.5 or over 2.5 goals.
Our predictions here are based on Poasson distribution on expected goals. So for under 2.5 goals we test all correct socre 0-0 1-0 2-0 1-1 0-1 and 0-2 and result is percent estimation for under 2.5. For over 2.5 we subtract 100-(under 2.5 %). Soccer predictions for other lines are based on same method.