A Short History of Probability Dr.Alan M.Polansky Division of Statistics Northern Illinois University
A Short History of Probability Dr. Alan M. Polansky Division of Statistics Northern Illinois University
French Society in the 1650's Gambling was popular and fashionable ■Not restricted by law ■As the games became more complicated and the stakes became larger there was a need for mathematical methods for computing chances. History of Probability 2
History of Probability 2 French Society in the 1650’s ! Gambling was popular and fashionable ! Not restricted by law ! As the games became more complicated and the stakes became larger there was a need for mathematical methods for computing chances
Enter the Mathematicians A well-known gambler, the chevalier De Mere consulted Blaise Pascal in Paris about a some questions about some games of chance. ■ Pascal began to correspond with his friend Pierre Fermat about these problems. History of Probability
History of Probability 3 Enter the Mathematicians ! A well-known gambler, the chevalier De Mere consulted Blaise Pascal in Paris about a some questions about some games of chance. ! Pascal began to correspond with his friend Pierre Fermat about these problems
Classical Probability The correspondence between Pascal and Fermat is the origin of the mathematical study of probability. The method they developed is now called the classical approach to computing probabilities. The method:Suppose a game has n equally likely outcomes,of which m outcomes correspond to winning.Then the probability of winning is m/n. History of Probability 4
History of Probability 4 Classical Probability ! The correspondence between Pascal and Fermat is the origin of the mathematical study of probability. ! The method they developed is now called the classical approach to computing probabilities. ! The method: Suppose a game has n equally likely outcomes, of which m outcomes correspond to winning. Then the probability of winning is m/n
Problems with the Classical Method The classical method requires a game to be broken down into equally likely outcomes. It is not always possible to do this. It is not always clear when possibilities are equally likely. History of Probability 5
History of Probability 5 Problems with the Classical Method ! The classical method requires a game to be broken down into equally likely outcomes. ! It is not always possible to do this. ! It is not always clear when possibilities are equally likely