Note: Not at the old Poker1 site.
Do you know what’s magic about making fewer than 21 football bets against a bookie or sports book? If you do it right, you’re just as likely to win as you are to lose, even if you don’t have a clue which team to bet!
Let me explain. In sports betting on basketball or football you typically must lay $110 for each $100 you want to win. Fine. This means you’re going to have to win 11 out of 21 bets, on average, just to break even (because 11 times you will have won $100 for a total of $1,100 and 10 times you will have lost $110 for the same total of $1,100).
Somebody must win
Now let’s eliminate the possibility of ties by assuming you only bet point spreads that are quoted in half points, such as 3½ or 7½ . With these “half point” lines, somebody must win, either you or the book. There can’t be a tie. Now, let’s assume you’re going to make an odd number of bets, so that your win and loss record cannot break even. When you make an uneven amount of wagers at half-point lines, either you or the book must win the majority. Nothing else is possible.
So, it turns out that if you make any odd number of bets fewer than 21 using half-point lines, you are just as likely to beat the bookie as the bookie is to beat you. There is no such thing as being an “underdog to win” by making 19 bets or 15 bets or three bets. If you have no information and are just flipping coins to pick winners, you have as good a chance of winning the majority of your bets as of losing the majority of your bets.
Your chance of winning is just as good as the sportsbook
The problem is that if you lose 10 out of 19, you’ve lost $200, but if you win 10 out of 19, you’ve only won $10. So, the sportsbook or bookie likes your bets and is earning a theoretical profit, but he doesn’t have the better chance of actually beating you until you make more than 21 bets. — Mike Caro (telling the truth about gambling)