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# L3 10 1

## by Jennifer Fasick on Jul 07, 2010

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Chapter 10 - Lesson 1

Chapter 10 - Lesson 1

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## L3 10 1Presentation Transcript

• EQ: How are the terms of probability used correctly to describe an event? Course 3 10-1 Probability
• Warm Up Write each fraction in simplest form. 1. 2. 3. 4. 8 64 Course 3 10-1 Probability 16 20 12 36 39 195 4 5 1 3 1 8 1 5
• Vocabulary experiment trial outcome sample space event probability impossible certain Insert Lesson Title Here Course 3 10-1 Probability
• experiment is an activity in which results are observed .
• Trial - Each observation
• Outcome - each result
• sample space is the set of all possible outcomes of an experiment .
Experiment Sample Space  flipping a coin  heads, tails  rolling a number cube  1, 2, 3, 4, 5, 6  guessing the number of  whole numbers marbles in a jar Course 3 10-1 Probability
• event is any set of one or more outcomes
• probability of an event, written P (event), is a number from 0 (or 0%) to 1 (or 100%) that tells you how likely the event is to happen .
• Impossible - probability of 0, meaning the event can never happen.
• Certain - probability of 1, means the event has to happen.
• The probabilities of all the outcomes in the sample space add up to 1.
Course 3 10-1 Probability
• 0 0.25 0.5 0.75 1 0% 25% 50% 75% 100% Never Happens about Always happens half the time happens 0 1 Course 3 10-1 Probability 1 4 1 2 3 4
• Give the probability for each outcome. Example #1 The basketball team has a 70% chance of winning. The probability of winning is P (win) = 70% = 0.7. The probabilities must add to 1, so the probability of not winning is P (lose) = 1 – 0.7 = 0.3, or 30%. Course 3 10-1 Probability
• Give the probability for each outcome. Example #2 Course 3 10-1 Probability Three of the eight sections of the spinner are labeled 1, so a reasonable estimate of the probability that the spinner will land on 1 is P (1) = . 3 8
• Give the probability for each outcome. With your partner – Example #3 Rolling a number cube. Course 3 10-1 Probability One of the six sides of a cube is labeled 1, so a reasonable estimate of the probability that the spinner will land on 1 is P (1) = . 1 6 Outcome 1 2 3 4 5 6 Probability One of the six sides of a cube is labeled 2, so a reasonable estimate of the probability that the spinner will land on 2 is P (2) = . 1 6
• Check It Out: Example 1B Continued Course 3 10-1 Probability One of the six sides of a cube is labeled 3, so a reasonable estimate of the probability that the spinner will land on 3 is P (3) = . 1 6 One of the six sides of a cube is labeled 4, so a reasonable estimate of the probability that the spinner will land on 4 is P (4) = . 1 6 One of the six sides of a cube is labeled 5, so a reasonable estimate of the probability that the spinner will land on 5 is P (5) = . 1 6
• Check It Out: Example 1B Continued Check The probabilities of all the outcomes must add to 1.  Course 3 10-1 Probability One of the six sides of a cube is labeled 6, so a reasonable estimate of the probability that the spinner will land on 6 is P (6) = . 1 6 1 6 1 6 1 6 + + = 1 1 6 + 1 6 + 1 6 +
• To find the probability of an event, add the probabilities of all the outcomes included in the event. Course 3 10-1 Probability
• A quiz contains 5 true or false questions. Suppose you guess randomly on every question. The table below gives the probability of each score. Example #4 What is the probability of guessing 3 or more correct? The event “three or more correct” consists of the outcomes 3, 4, and 5. P (3 or more correct) = 0.313 + 0.156 + 0.031 = 0.5, or 50%. Course 3 10-1 Probability
• What is the probability of guessing fewer than 2 correct? The event “fewer than 2 correct” consists of the outcomes 0 and 1. P (fewer than 2 correct) = 0.031 + 0.156 = 0.187, or 18.7% Example #5 A quiz contains 5 true or false questions. Suppose you guess randomly on every question. The table below gives the probability of each score. Course 3 10-1 Probability
• What is the probability of passing the quiz (getting 4 or 5 correct) by guessing? The event “passing the quiz” consists of the outcomes 4 and 5. P (passing the quiz) = 0.156 + 0.031 = 0.187, or 18.7% Additional Example 2C: Finding Probabilities of Events A quiz contains 5 true or false questions. Suppose you guess randomly on every question. The table below gives the probability of each score. Course 3 10-1 Probability
• A quiz contains 5 true or false questions. Suppose you guess randomly on every question. The table below gives the probability of each score. Check It Out: Example 2A What is the probability of guessing 2 or more correct? The event “two or more correct” consists of the outcomes 2, 3, 4, and 5. P (2 or more) = 0.313 + 0.313 + 0.156 + 0.031 = .813, or 81.3%. Course 3 10-1 Probability
• Lesson Quiz Use the table to find the probability of each event. 1. 1 or 2 occurring 2. 3 not occurring 3. 2, 3, or 4 occurring 0.874 0.351 Insert Lesson Title Here 0.794 Course 3 10-1 Probability
• Ticket Out: What is the difference between an outcome and an event? Course 3 10-1 Probability