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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 3.2.23c

"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)
c. Find the probability that at least one of the two probable voters would like entertainers to address social and political issues."

Verified step by step guidance
1
Step 1: Understand the problem. We are tasked with finding the probability that at least one of the two probable voters selected at random would like entertainers to address social and political issues. This involves using the complement rule and the multiplication rule.
Step 2: Define the probabilities. From the problem, we know that three out of four voters (or 75%) would like entertainers to address social and political issues. Thus, the probability of a voter liking this is P(A) = 0.75, and the probability of a voter not liking this is P(A') = 1 - 0.75 = 0.25.
Step 3: Use the complement rule. The probability of 'at least one' liking the issue is the complement of the probability that 'none' of the two voters like the issue. Mathematically, P(at least one) = 1 - P(none).
Step 4: Calculate P(none). To find P(none), use the multiplication rule. Since the two voters are selected independently, the probability that both do not like the issue is P(A') * P(A'). Substituting the values, P(none) = 0.25 * 0.25.
Step 5: Substitute into the complement formula. Finally, substitute P(none) into the complement formula: P(at least one) = 1 - P(none). This gives the probability that at least one of the two voters would like entertainers to address social and political issues.

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Key Concepts

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

Multiplication Rule

The Multiplication Rule in probability states that the probability of two independent events both occurring is the product of their individual probabilities. This rule is essential for calculating the likelihood of multiple outcomes happening together, especially when events do not influence each other.
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Multiplication Rule: Dependent Events

Complementary Events

Complementary events are pairs of outcomes in a probability scenario where one event occurs if and only if the other does not. In this context, finding the probability that at least one of the two voters supports entertainers addressing social issues can be simplified by calculating the probability that neither does and subtracting it from one.
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Complementary Events

Probability Calculation

Probability calculation involves determining the likelihood of an event occurring, expressed as a number between 0 and 1. In this problem, the probability of a voter wanting entertainers to address issues is 0.75, and the probability of not wanting this is 0.25, which are crucial for applying the Multiplication Rule and finding the desired probability.
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Related Practice
Textbook Question

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

25. Best President In a sample of 1500 adult U.S. citizens, 270 said that Barack Obama was the best president in U.S. history. Two adult U.S. citizens are selected at random.

(Adapted from YouGov)

c. Find the probability that at least one of the two adult U.S. citizens says that Barack Obama was the best president in U.S. history."

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Textbook Question

"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)

c. Find the probability that at least one of the four has lost a friend or relative to murder."

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Textbook Question

19. U.S. Age Distribution The projected percent distribution of the U.S. population for 2025 is shown in the pie chart. Find the probability of each event. (Source: U.S. Census

Bureau)

c. Randomly selecting someone who is not 60 years or over

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Textbook Question

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

27. Blood Types The probability that a person of Asian descent in the United States has type O+ blood is 39%. At random, six people of Asian descent in the United States are selected. (Source: American National Red Cross)

c. Find the probability that at least one of the six has type O+ blood.

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Textbook Question

88. Individual Stock Price An individual stock is selected at random from the portfolio represented by the box-and-whisker plot shown. Find the probability that the stock price is between \$21 and \$50.

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Textbook Question

17. Selecting a Card A card is selected at random from a standard deck of 52 playing cards. Find the probability of each event.

c. Randomly selecting a 9 or a face card

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