Lesson 3A: Probability & Odds

The young man is stating his opinion of the chance of rain in the afternoon. His statement sixty - forty refers to the chance of rain and the chance of no rain. He believes there is a 60% chance that it will rain, which means a 40% chance that it will not rain. By comparing in this way, the man is expressing the odds in favour of rain in the afternoon.

You may have heard a sports-caster report the odds of a team winning a game as three-to-one. This is a statement of odds against the team winning. It means for every four games played, the team is expected not to win (which is to lose) three and win one. Stating odds against is the norm in sports reporting.

Another area where odds are used is in gambling.

Most people who gamble, whether it be casinos, horse races, or lottery tickets, do not know the odds of winning - they know only that the chances of winning are low!

Many people dream about what they would do if they won the lottery. However, consider the following scenario. Imagine a swimming pool filled with almost 14 million jellybeans. Hidden among the millions is one black jellybean. Put on a blindfold and wade through the candies. Then, stop, reach down, and select one jellybean. Will you choose the black one? Your chances of selecting the black jellybean are almost the same as your chances of selecting the correct 6-number combination of 49 numbers in a popular lottery!

As long as gambling is just for fun, the odds in favour of winning should not be a concern. Unfortunately, people become addicted to gambling and spend more money than they intend. In this case, the perceived odds of winning drive them to continue. This is a cause for concern. Not gambling at all is best, but if a person tries his or her luck, then he or she must be prepared to lose most of the time!

As the previous examples show, odds are used in many facets of the real world. They are often confused with probability and most people think of them as the same thing. They are closely related, but they are not the same. Odds involve the ratio of events that will occur and events that will not occur. Probability is the ratio of events that will occur to the total number of events.

In this Training Camp you will investigate the relationship between odds and probability in detail.

By the end of this lesson, you should be able to

	express odds as a probability and vice versa
	determine the probability of, or the odds for and against, an outcome
	solve a problem that involves odds or probability