Teacher resources and professional development across the curriculum
Teacher professional development and classroom resources across the curriculum
Statistics as Problem Solving
Making Sense of Randomness
Place Your Bets: Cashing in on Probability
Thinking about going to a casino to play roulette and win a bundle? There's something you should know before you ante up. It's much more likely that the casino will win than you will.
The roulette wheel is divided into 38 numbered slots. Two of these slots are green, 18 are red, and 18 are black. To begin the round, the wheel is spun and a ball is dropped onto its outside edge. When the wheel stops, the ball drops into 1 of the 38 slots.
Players bet on which slot they believe the ball will land in. If you bet your money that the ball will land in any of the 18 red slots, your chances of winning are 18 out of 38. If you bet your money on a certain number, such as the red slot numbered with a 10, your chances of winning drop to 1 in 38.
Playing the odds
Both you and the people who own the casino are gamblingplaying the oddsbut the odds that the casino owner will win are much greater than the odds that you will win. In fact, the mathematics of probability guarantee that the owners of the roulette wheel will make money with that wheel, even if they don't win every time. This is no accident of fate. It's the way the game is constructed.
Remember those colored slots? There are 18 each of the red and black slots. There are also 2 green slots. Whenever the ball lands in 1 of those green slots, the house wins everything that was bet on that round. So again, let's say you bet that the ball will land in a red slot (or, for that matter, a black slot). This is the safest possible bet in roulette, since the odds are 18 out of 38 that you'll win. But they're 20 out of 38 that you'll lose.
If you spend day after day at the roulette table, you will consistently lose over time. But for any given night, the outcome of your bets is much less predictable. You might beat the odds and take home a pocketful of cash, or you might lose fistfuls of money. The casino is not taking any chances, though. The odds make it certain that, over time, the casino will consistently turn a profit.