Date: Sun, 19 Jul 1998 10:23:08 EDT
Subject: Probability

Great resource!
Would you please advise me what the probability is of rolling snake eyes on a pair of dice is? My recollection is 1 out of 6 multiplied by 1 out of 6 = 1 out of 36 is this correct?

thanks for your help
You are right if we are talking about the theoretical probability of rolling a pair of perfect dice in a perfect manner. Think of the two dice as one red and one green, and imagine rolling the dice a large number of times. You would expect to see a "one" on the red die about one sixth of the times, and of all of the times you see a "one" on the red die you expect about one sixth of these to also have a "one" on the green die. Thus you would expect to see snake eyes approximately one sixth of one sixth of the number of times you rolled the dice.

In his book The Jungles of Randomness, Ivers Peterson discusses some of the difficulities in producing perfect dice and ideal settings that Casinos face in attempting to create a situation where the practice of rolling real dice and the theoretical probabilities agree.

Happy rolling!
Jack and Penny

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