1. Holt CA Course 1 8-2 Experimental Probability SDAP3.2 Use data to estimate the probability of future events (e.g., batting averages or number of accidents per mile driven). Also covered: SDAP3.3 California Standards

2. Holt CA Course 1 8-2 Experimental Probability Vocabulary experimental probability

3. Holt CA Course 1 8-2 Experimental Probability Experimental probability is one way of estimating the probability of an event. The experimental probability of an event is found by comparing the number of times the event occurs to the total number of trials when repeating an experiment many times. The more trials you have, the more accurate the estimate is likely to be.

4. Holt CA Course 1 8-2 Experimental Probability

5. Holt CA Course 1 8-2 Experimental Probability During skating practice, Sasha landed 7 out of 12 jumps. What is the experimental probability that she will land her next jump? Write your answer as a ratio, as a decimal, and as a percent. Then explain why your answer is reasonable. Additional Example 1: Sports Application P(event)  number of times an event occurs total number of trials Substitute data from the experiment. 7 12 = number of jumps landed number of jumps attempted P(jumps landed)  ≈ 0.583 ≈ 58.3% Write as a decimal and as a percent.

6. Holt CA Course 1 8-2 Experimental Probability Additional Example 1 Continued The experimental probability that Sasha will land her next jump is or 0.583, or 58.3%. 7 12 Sasha landed about half, or 50%, of the 12 jumps, so an answer of 58.3% is reasonable. During skating practice, Sasha landed 7 out of 12 jumps. What is the experimental probability that she will land her next jump? Write your answer as a ratio, as a decimal, and as a percent. Then explain why your answer is reasonable.

7. Holt CA Course 1 8-2 Experimental Probability “P(event)” represents the probability that an event will occur. For example, the probability of a flipped coin landing heads up could be written as “P(heads).” Writing Math

8. Holt CA Course 1 8-2 Experimental Probability Check It Out! Example 1 During basketball practice, Martha made 9 out of 10 free throws. What is the experimental probability that she will make her next attempt? Write your answer as a ratio, as a decimal, and as a percent. Then explain why your answer is reasonable. P(event)  number of times an event occurs total number of trials Substitute data from the experiment and write as a percent. 9 10 = P(free throws made)  number of free throws made number of free throws attempted = 0.9 = 90% Write as a decimal and as a percent.

9. Holt CA Course 1 8-2 Experimental Probability Check It Out! Example 1 Continued The experimental probability that Martha will make the next free throw is, or 0.9, or 90%. 9 10 Martha made almost all, or 100%, of the 10 free throws, so an answer of 90% is reasonable. During basketball practice, Martha made 9 out of 10 free throws. What is the experimental probability that she will make her next attempt? Write your answer as a ratio, as a decimal, and as a percent. Then explain why your answer is reasonable.

10. Holt CA Course 1 8-2 Experimental Probability Students have checked out 55 books from the library. Of these, 32 books are fiction. Additional Example 2: Application A. What is the experimental probability that the next book checked out will be fiction? P(fiction)  number of fiction books checked out total number of books checked out = 32 55 The experimental probability that the next book checked out will be fiction is 32 55. Substitute data.

11. Holt CA Course 1 8-2 Experimental Probability B. What is the experimental probability that Additional Example 2: Application the next book checked out will be nonfiction? P(fiction) + P(nonfiction) = 1 + P(nonfiction) = 1 The experimental probability that the next book checked out will be nonfiction is approximately 23 55. Substitute. 32 55 Use the complement. Subtract from both sides. 32 55 P(nonfiction) = 23 55 32 55 –=– 32 55  Students have checked out 55 books from the library. Of these, 32 books are fiction.

12. Holt CA Course 1 8-2 Experimental Probability Check It Out! Example 2 Students have a fruit choice of either an apple or a pear. So far 18 of 47 students have selected pears. A. What is the experimental probability that the next fruit selected will be a pear? = 18 47 The experimental probability that the next fruit selected will be a pear is 18 47. Substitute data. P(pear)  number of pears selected total number of fruit selected

13. Holt CA Course 1 8-2 Experimental Probability Check It Out! Example 2 P(pear) + P(apple) = 1 + P(apple) = 1 The experimental probability that the next fruit selected will be an apple is 29 47. Substitute. 18 47 Use the complement. Subtract from both sides. 18 47 P(apple) = 29 47 18 47 –=– 18 47  B. What is the experimental probability that next fruit selected will be an apple? Students have a fruit choice of either an apple or a pear. So far 18 of 47 students have selected pears.