Lesson 1.2 Probability

What is Probability?

Probability is the mathematical tool used to study randomness. If you toss a coin or roll dice, you cannot predict the result in advance. But, after many repetitons of tossing the coin or rolling the dice, a pattern will emerge. You will find that, on average, "heads" (the head sign of the coin) comes up approximately 50% of the time. Not only that, but the more times you flip the coin, the closer the average gets to 50%. The theory of probability is based on this amazing fact.

Some Probability History

"A gambler's dispute in 1654 led to the creation of a mathematical theory of probability by two famous French mathematicians, Blaise Pascal and Pierre de Fermat. Antoine Gombaud, Chevalier de Méré, a French nobleman with an interest in gaming and gambling questions, called Pascal's attention to an apparent contradiction concerning a popular dice game. The game consisted in throwing a pair of dice 24 times; the problem was to decide whether or not to bet even money on the occurrence of at least one "double six" during the 24 throws. A seemingly well-established gambling rule led de Méré to believe that betting on a double six in 24 throws would be profitable, but his own calculations indicated just the opposite."

Think about it:
If you toss a six-sided die 6,000 times, about how many times would you roll the number "six"? On the 6,001^st roll, what would be the probability of rolling another "six"?

Another Probability Example

To further examine your understanding of probability, test your ability to figure the probability that bears are male. This bear example will open in a new browser window. To return to this page, just close (or move or minimize) the window with the bears and you will return right here.

Please continue to the next section of this lesson.

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