Would you accept a bet last week for $100.00 that the Cardinals would beat the Rams and you had to bet for the Cardinals?
No one other than a complete fool would take that bet so in order for the big casino bookmakers to get bets (action) on both sides they create a points spread to entice others to bet on what would otherwise be a weaker team. At kickoff last week the Cardinals were fourteen point underdogs (meaning they were +14). If you bet on the Cardinals, you got to add 14 points to the final score. So if the game was rams 34 and Cardinals 21, the Cardinals would have won with the points spread because you add 14 points to the final score to give you Rams 34 and Cardinals 35 with the point spread. So the Rams would have Won the game but lost against the spread.
This rams team not only won, but easily covered the 14 point point spread because Rams 34 and Cardinals 0 = Rams 34 Cardinals 14 with the points.
Now the game is Rams -7 (same as saying the Chargers are +7). Chargers are 7 point under dogs meaning to win a bet, the Rams have to win more than 7. Almost everyone thinks the Rams will win the game but some have reservations that the Rams will also cover the spread. In other words, any final score in which the Rams don't win by more than 7, they will not have covered the point spread though the still may win the game. For example Rams 28 Chargers 24 = Win outright but a loss against the spread.
For most bets, the casinos require you to bet $11.00 to make $10.00. So they can make a good chunk of money if they get action on both sides and just clip the "juice". The juice being the $1.00 on $11.00 which goes to the house.
The over under line is much easier and there is no science to it. The Odds makers basically average out (with some adjustments) how many points these teams average and add them together to create the over under line. If you think the combined score will go over then you pick the over. If you think the combined score will be under you take the under. Again you have to bet $11.00 to make ten on most over under lines. The over under on the Rams Raiders I believe was 48 points. The combined score, 33 - 13, was 36 point so the "under" was the winner.
