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Ch. 3 - Probability
Larson - Elementary Statistics: Picturing the World 8th Edition
Larson8th EditionElementary Statistics: Picturing the WorldISBN: 9780137493470Not the one you use?Change textbook
Chapter 3, Problem 3.2.24b

"Using the Multiplication Rule In Exercises 19-32, use the Multiplication Rule.
24. Knowing a Person Who Was Murdered In a sample of 11,771 children ages 2 to 17, 8% have lost a friend or relative to murder. Four children are selected at random. (Adapted from University of New Hampshire)
b. Find the probability that none of the four has lost a friend or relative to murder."

Verified step by step guidance
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Step 1: Understand the problem. We are tasked with finding the probability that none of the four randomly selected children has lost a friend or relative to murder. This involves using the Multiplication Rule for independent events.
Step 2: Define the probability of the complementary event. The problem states that 8% of children have lost a friend or relative to murder. Therefore, the probability that a child has NOT lost a friend or relative to murder is 1 - 0.08 = 0.92.
Step 3: Recognize that the four children are selected independently. This means the outcome for one child does not affect the outcomes for the others. The Multiplication Rule for independent events states that the probability of all events occurring is the product of their individual probabilities.
Step 4: Apply the Multiplication Rule. To find the probability that none of the four children has lost a friend or relative to murder, multiply the probability of the complementary event (0.92) by itself four times: \( P(\text{none}) = 0.92 \times 0.92 \times 0.92 \times 0.92 \).
Step 5: Simplify the expression. This can also be written as \( P(\text{none}) = 0.92^4 \). Use this formula to calculate the final probability if needed.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Multiplication Rule of Probability

The Multiplication Rule states that the probability of two independent events both occurring is the product of their individual probabilities. In this context, it helps calculate the likelihood of multiple children not having lost a friend or relative to murder by multiplying the probabilities of each child independently not experiencing this loss.
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Multiplication Rule: Dependent Events

Complementary Probability

Complementary probability refers to the probability of an event not occurring. In this scenario, if 8% of children have lost someone to murder, then 92% have not. This concept is crucial for determining the probability that none of the selected children have experienced this loss, as it allows us to use the probability of the complementary event.
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Complementary Events

Independent Events

Independent events are those whose outcomes do not affect each other. In this problem, the selection of each child is independent, meaning the probability of one child not having lost someone to murder does not change based on the selections of the others. This independence is essential for applying the Multiplication Rule correctly.
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Probability of Multiple Independent Events
Related Practice
Textbook Question

"Using the Multiplication Rule In Exercises 19-32, use the Multiplication Rule.

23. Celebrities as Role Models In a sample of 1103 probable voters, three out of four say they would like entertainers to address social and political issues. Two probable voters are selected at random. (Source: The Hollywood Reporter)

b. Find the probability that neither probable voter would like entertainers to address social and political issues."

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Textbook Question

Politics The responses of 1500 U.S. adults to a survey that asked them to state their own political viewpoints are shown in the Pareto chart. Find the probability of each event.(Adapted from YouGov)

b. Randomly selecting a person from the sample who is conservative or very conservative

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Textbook Question

Finding Conditional Probabilities In Exercises 7 and 8, use the table to find each conditional probability.

8. Retirement Savings The table shows the results of a survey in which 250 male and 250 female workers ages 25 to 64 were asked if they contribute to a retirement savings plan at

work.

b. Find the probability that a randomly selected worker is female, given that the worker contributes to a retirement savings plan at work.

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Textbook Question

2. Determine whether each number could represent the probability of an event. Explain your reasoning. b. 333.3%

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Textbook Question

Officers The offices of president, vice president, secretary, and treasurer for an environmental club will be filled from a pool of 14 candidates. Six of the candidates are members of the debate team.

b. What is the probability that none of the offices are filled by members of the debate team?

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Textbook Question

22. Brexit A survey asked 1115 British adults how Britain's decision to leave the European Union has impacted the country. The results are shown in the Pareto chart. Find the

probability of each event. (Adapted from Ipsos)

b. Randomly selecting a British adult who feels that the move has had a very negative impact on Great Britain

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