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# If you bet colors at roulette, should you pick the same or opposite whatever just hit?

9 September 2013

Question: Some friends of mine bet on the same color at roulette – red or black – that's just hit, thinking this raises their odds of winning. I don't think previous results matter. Do you?

Answer: You're correct. Apparent "patterns" have no meaning. Roulette is a game of independ-ent trials. Probabilities associated with the bets are invariable. The chance of winning on red or black at a double-zero table, for instance, is always 47.37 percent.

Here's one reason many folks believe that results, especially colors, tend to clump. They look at the displays at each table and see runs of multiple wins in the red or the black columns. But the laws of probability predict these will occur in random series of fixed-odds events. I'll put some numbers on the phenomenon for you, assuming a display of 24 previous numbers.

Would you think you were onto something significant if you saw eight or more instances of black-black or red-red, including cases of over two in a row? Don't be fooled. There's a 70 percent chance it will happen. How about four or more instances of at least triplets? The chance is slightly over 50 percent. Is a run of five or more successive reds or blacks unusual? Not really – the probability is nearly 25 percent.

Try it at home with 20 series of 24 flips of a coin, jotting down heads or tails. You may be surprised at how many pairs and longer runs you get, knowing every flip is a 50-50 proposition.
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Best of Alan Krigman
Alan Krigman

Alan Krigman was a weekly syndicated newspaper gaming columnist and Editor & Publisher of Winning Ways, a monthly newsletter for casino aficionados. His columns focused on gambling probability and statistics. He passed away in October, 2013.
Alan Krigman
Alan Krigman was a weekly syndicated newspaper gaming columnist and Editor & Publisher of Winning Ways, a monthly newsletter for casino aficionados. His columns focused on gambling probability and statistics. He passed away in October, 2013.