Roulette Wheel Odds

Saturday, April 21, 2007

...Even David Mamet makes mistakes...

I

started reading David Mamet's Bambi vs. Godzilla: On the Nature, Purpose, and Practice of the Movie Business.

In his chapter on producers, he compares a movie producer to a casino gambler who bets black on a roulette wheel. After the first loss, he bets black again but with twice the money and keeps this up until he wins.

Movie producers keep betting more money on the tent pole movies with the hopes it will be the next JAWS or STAR WARS. If the movie fails, the producer can't be blamed because he didn't cut any corners. "We doubled our budget."

The strategy he insists is doomed to fail just like the gambler.

When he writes that there is a limited bankroll for both the gambler and producer, it's easy to understand even for a multibillion dollar company. They may very well run out of funds before their strategy pays off.

And he's correct when he writes about the independent nature of each roll of the wheel. That it came up black on the last roll has no bearing on whether it will be black or red the next time. The odds on each spin of the wheel are the same each time unlike the draw of a card in blackjack or poker.

But he's wrong about the odds on black or red coming up.

The odds of its appearance on the next spin are still 50-50.

Close, but no. In a Las Vegas roulette wheel there are 18 red numbers, 18 black numbers and 2 green numbers for a total of 38.

The odds for a fair coin toss is 50-50 since there are only two outcomes: heads or tails. To get the same odds for red or black on a roulette wheel, the green pocket would have to be removed, but since it's there, the chance of getting red or black is slightly less than 50% of the time. It's exactly 47.3684% (18/38).

In Europe, your chance of winning with black or red increase since they use one green pocket, zero, and don't have the second double-zero green.

P.S. I've never been to Las Vegas and I'm not a casino gambler. I don't get seduced by the possibility of hitting a jackpot.

I remember during a summer trip when I was in my early teens where on a ferry between Maine and Nova Scotia there were slot machines. I watched what was going on instead of playing. I remember two men who started with a couple of rolls of quarters, played until they doubled or tripled their money, they were all giddy, then lost it all and looked deflated. I imagine that happens everyday.

Posted 2007/04/21 at 17h58ET in Movies.