Define and Use ProbabilitySection 10.3

Objectives:Define probability

Find the likelihood that an event will occur

Key Vocabulary:ProbabilityTheoretical probabilityOddsExperimental probabilityGeometric probability

ProbabilityThe probability of an event is a

number from 0 to 1 that indicates the likelihood the event will occur, as shown on the number line below. Probabilities can be written as fractions, decimals, or percents.

Theoretical Probability

Example 1:You roll a standard six-sided die.

Find the probability of (a) rolling a 5 and (b) rolling an even number.

Example 2:A community center hosts a talent contest for local

musicians. On a given evening, 7 musicians are scheduled to perform. The order in which the musicians perform is randomly selected during the show.

a) What is the probability that the musicians perform in alphabetical order by their last names? (Assume that no two musicians have the same last name.)

b) You are friends with 4 of the musicians. What is the probability that the first 2 performers are your friends?

#1: You have an equally likely chance of choosing any integer from 1 through 20. Find the probability of the given event.

A perfect square is chosen.

#2: You have an equally likely chance of choosing any integer from 1 through 20. Find the probability of the given event.

A factor of 30 is chosen.

Odds

Example 3:A card is drawn from a standard

deck of 52 cards. Find (a) the odds in favor of drawing a 10 and (b) the odds against drawing a club.

Experimental Probability

Example 4:The bar graph shows how old

adults in a survey would choose to be if they could choose any age. Find the experimental probability that a randomly selected adult would prefer to be at least 40 years old.

#4: A card is randomly drawn from a standard deck. Find the indicated odds.

In favor of drawing a heart.

#5: A card is randomly drawn from a standard deck. Find the indicated odds.

Against drawing a queen.

Example 5:You throw a dart at the square dart

board shown. Your dart is equally likely to hit any point inside the board. Are you more likely to get 10 points or 0 points?

Homework AssignmentPage 701 #4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 28, 30, 32, 36, 38, 42 (a&b)