Probability and Random Events in Math: Learn with Examples

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3. Example 1-3b Objective Find the probability of a simple event

4. Example 1-3b Vocabulary Outcome One possible result of a probability event

5. Example 1-3b Vocabulary Simple event One outcome or a collection of outcomes

6. Example 1-3b Vocabulary Probability The chance that some event will happen. A ratio Ways an event can occur Number of Possible Outcomes

7. Example 1-3b Vocabulary Random Outcomes occur at random if each outcome is equally likely to occur

8. Example 1-3b Vocabulary Complementary event The events of one outcome happening and that outcome not happening are complementary events. The sum of the probabilities of complementary events is 1

9. Lesson 1 Contents Example 1Find Probability Example 2Find Probability Example 3Find a Complementary Event

10. Example 1-1a If the spinner is spun once, what is the probability of it landing on an odd number? odd number Write probability statement Numerator is “odd numbers possible” Denominator is “total numbers possible” 1/3

11. Example 1-1a If the spinner is spun once, what is the probability of it landing on an odd number? Count how many “odd numbers” 1 and 3 are odd numbers Place 2 in the numerator 1/3

12. Example 1-1a If the spinner is spun once, what is the probability of it landing on an odd number? Count how many “total numbers” are on the spinner There are 4 numbers on the spinner Place 4 in the denominator 1/3

13. Example 1-1a If the spinner is spun once, what is the probability of it landing on an odd number?  2 Find the GCF = 2  2 Divide GCF into numerator and denominator Answer: 1/3

14. Example 1-1c What is the probability of rolling a number less than three on a number cube marked with 1, 2, 3, 4, 5, and 6 on its faces? NOTE: A number cube is a number dice Answer: P (number less than 3) = 1/3

15. Example 1-2a The bookstore at the mall has 15 math books, 20 science books, 10 literature books and 5 history books for a give-away promotion. The clerk will select a book at random to give to each customer. What is the probability that the clerk will select a literature book? probability literature book number of literature books P (literature book) = total number of books Write probability statement Numerator will be “number of literature books” Denominator will be “total number of books” 2/3

16. Example 1-2a The bookstore at the mall has 15 math books, 20 science books, 10 literature books and 5 history books for a give-away promotion. The clerk will select a book at random to give to each customer. What is the probability that the clerk will select a literature book? probability literature book number of literature books P (literature book) = total number of books 10 Replace literature books with 10 P (literature book) = 50 Count total number of books 15 + 20 + 10 + 5 = 50 2/3

17. Example 1-2a The bookstore at the mall has 15 math books, 20 science books, 10 literature books and 5 history books for a give-away promotion. The clerk will select a book at random to give to each customer. What is the probability that the clerk will select a literature book? probability literature book number of literature books P (literature book) = total number of books  10 = 10 10 Find the GCF P (literature book) =  10 50 Divide GCF into numerator and denominator Answer: 1 P (literature book) = 5 2/3

18. Example 1-2c GAMESA game requires rolling a number cube marked with 1, 2, 3, 4, 5, and 6 on its. If the roll is four or less, the player wins. What is the probability of winning the game? Answer: 2 P (4 or less) = 3 2/3

19. Example 1-3a GAMESA game requires spinning the spinner. If the spin is 6 or greater, the player wins. What is the probability of not winning the game? probability of not winning P (5 or less) = Write probability statement To win, must have 6 or greater So to lose, must have 5 or less 3/3

20. Example 1-3a GAMESA game requires spinning the spinner. If the spin is 6 or greater, the player wins. What is the probability of not winning the game? probability of not winning numbers 5 or less P (5 or less) = total number of numbers Numerator is “numbers 5 or less” Denominator is “total number of numbers” 3/3

21. Example 1-3a GAMESA game requires spinning the spinner. If the spin is 6 or greater, the player wins. What is the probability of not winning the game? probability of not winning numbers 5 or less P (5 or less) = total number of numbers 5 P (5 or less) = Count numbers that are 5 or less 8 Count all the numbers 3/3

22. Example 1-3a GAMESA game requires spinning the spinner. If the spin is 6 or greater, the player wins. What is the probability of not winning the game? probability of not winning numbers 5 or less P (5 or less) = total number of numbers Answer: 5 P (5 or less) = = 1 Find the GCF 8 NOTE: This is a complementary event 3/3

23. Example 1-3b * GAMESA game requires rolling a number cube marked with 1, 2, 3, 4, 5, and 6 on its faces. If the roll is two or less, the player wins. What is the probability of not winning the game? Answer: 2 P (not winning) = 3 NOTE: This is a complementary event 3/3

24. End of Lesson 1 Assignment