/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 62 Let \(F\) denote the event that ... [FREE SOLUTION] | 91Ó°ÊÓ

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Let \(F\) denote the event that a randomly selected registered voter in a certain city has signed a petition to recall the mayor. Also, let \(E\) denote the event that a randomly selected registered voter actually votes in the recall election. Describe the event \(E \cap F\) in words. If \(P(F)=.10\) and \(P(E \mid F)=.80\), determine \(P(E \cap F)\).

Short Answer

Expert verified
The probability that a randomly selected voter signed the petition and actually votes in the recall election is 0.08.

Step by step solution

01

Understanding the events

The event \(E \cap F\) stands for the situation where a randomly selected registered voter in this city has both signed the petition to recall the mayor (Event \(F\)) and actually votes in the recall election (Event \(E\)). In terms of probability, this is represented by \(P(E \cap F)\).
02

Using the conditional probability formula

The definition of conditional probability is \(P(A \mid B) = P(A \cap B)/P(B)\). We are given \(P(F)\) as 0.10 and \(P(E \mid F)\) as 0.80. We can use these values to calculate \(P(E \cap F)\) by rearranging the definition of conditional probability to \(P(E \cap F) = P(E \mid F) \times P(F)\).
03

Calculating the probability of E and F

Substitute the known values into the rearranged formula. So, \(P(E \cap F) = P(E \mid F) \times P(F) = 0.80 \times 0.10\).

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Probability Theory
Probability theory forms the backbone of statistical analysis and is fundamental to understanding and predicting outcomes in a random process. The basics involve concepts such as random events, outcomes, and their respective probabilities.

When we define events in probability, they describe specific outcomes or sets of outcomes. For example, in our exercise, the event labeled as 'F' signifies the outcome in which a person has signed a petition, and 'E' represents that the same person has voted in the recall election.

The probability of an event is a measure of the likelihood that the event will occur, expressed as a number between 0 and 1, where 0 indicates the event will not occur, and 1 signifies certainty. In the context of our exercise, the given probabilities, such as the 10% chance that a voter signed the petition (\(P(F)=0.10\)) and the 80% chance that a voter who signed the petition will also vote in the election (\(P(E \text{ given } F)=0.80\)), provide us with numerical insight into the voters' behavior.
Statistical Analysis
Statistical analysis involves collecting, exploring, and presenting large quantities of data to discover underlying patterns and trends. Part of this analysis is determining the relationship between two events, which is where concepts like joint probability and conditional probability come into play.

To assess the connection between two events, the analysis might center around whether the occurrence of one event affects the probability of another event happening, known as conditional probability. A clear understanding of these relationships is crucial in many fields, such as social science, where our original exercise comes from. It allows statisticians to make predictions, such as voter turnout, based on known behaviors, like petition signing.

Our exercise illustrates how these probabilities can be applied by using the given data (\(P(F)\) and \(P(E \text{ given } F)\) to elucidate the intersection of two events, which in turn may provide valuable insights for political analysts.
Event Intersection
To discuss the intersection of events in probability theory, it's necessary to understand that it relates to the occurrence of two or more events simultaneously. In our exercise, the intersection (\(E \text{ intersect } F\text{ or } E \text{ cap } F\)) would be the group of people who have both signed the petition and voted in the election.

The probability of the intersection of two events can be found if we know the conditional probability of one event happening given that the other has already occurred. This is where the formula \[P(A \text{ intersect } B) = P(A \text{ given } B) \times P(B)\] comes into play. In simpler terms, this means that to find how likely it is for both events to happen, you would multiply the likelihood of one event by the probability that the other event happens too.

An accurate calculation of event intersections can provide valuable predictions in many scenarios, such as understanding the demographics of voters actively engaging in an election process, as highlighted by our textbook example.

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Most popular questions from this chapter

Of the 10,000 students at a certain university, 7000 have Visa cards, 6000 have MasterCards, and 5000 have both. Suppose that a student is randomly selected. a. What is the probability that the selected student has a Visa card? b. What is the probability that the selected student has both cards? c. Suppose you learn that the selected individual has a Visa card (was one of the 7000 with such a card). Now what is the probability that this student has both cards? d. Are the events has \(a\) Visa card and has a MasterCard independent? Explain. e. Answer the question posed in Part (d) if only 4200 of the students have both cards.

The Los Angeles Times (June 14,1995 ) reported that the U.S. Postal Service is getting speedier, with higher overnight on-time delivery rates than in the past. The Price Waterhouse accounting firm conducted an independent audit by seeding the mail with letters and recording ontime delivery rates for these letters. Suppose that the results were as follows (these numhers are fictitions hut are compatible with summary values given in the article): $$ \begin{array}{lcc} & \begin{array}{l} \text { Number } \\ \text { of Letters } \\ \text { Mailed } \end{array} & \begin{array}{l} \text { Number of } \\ \text { Lefters Arriving } \\ \text { on Time } \end{array} \\ \hline \text { Los Angeles } & 500 & 425 \\ \text { New York } & 500 & 415 \\ \text { Washington, D.C. } & 500 & 405 \\ \text { Nationwide } & 6000 & 5220 \\ & & \\ \hline \end{array} $$ Use the given information to estimate the following probabilities: a. The probability of an on-time delivery in Los Angeles b. The probability of late delivery in Washington, D.C. c. The probability that two letters mailed in New York are both delivered on time d. The probability of on-time delivery nationwide

Define the term chance experiment, and give an example of a chance experiment with four possible outcomes.

A single-elimination tournament with four players is to be held. In Game 1 , the players seeded (rated) first and fourth play. In Game 2, the players seeded second and third play. In Game 3 , the winners of Games 1 and 2 play, with the winner of Game 3 declared the tournament winner. Suppose that the following probabilities are given: \(P(\) seed 1 defeats seed 4\()=.8\) \(P(\) seed 1 defeats seed 2\()=.6\) \(P(\) seed 1 defeats seed 3\()=.7\) \(P(\) seed 2 defeats seed 3\()=.6\) \(P(\) seed 2 defeats seed 4\()=.7\) \(P(\) seed 3 defeats seed 4\()=.6\) a. Describe how you would use a selection of random digits to simulate Game 1 of this tournament. b. Describe how you would use a selection of random digits to simulate Game 2 of this tournament. c. How would you use a selection of random digits to simulate Game 3 in the tournament? (This will depend on the outcomes of Games 1 and 2.) d. Simulate one complete tournament, giving an explanation for each step in the process. e. Simulate 10 tournaments, and use the resulting information to estimate the probability that the first seed wins the tournament. f. Ask four classmates for their simulation results. Along with your own results, this should give you information on 50 simulated tournaments. Use this information to estimate the probability that the first seed wins the tournament. g. Why do the estimated probabilities from Parts (e) and (f) differ? Which do you think is a better estimate of the true probability? Explain.

A company uses three different assembly lines \(-A_{1}\), \(A_{2}\), and \(A_{3}-\) to manufacture a particular component. Of those manufactured by \(A_{1}, 5 \%\) need rework to remedy a defect, whereas \(8 \%\) of \(A_{2}\) 's components and \(10 \%\) of \(A_{3}\) 's components need rework. Suppose that \(50 \%\) of all components are produced by \(A_{1}\), whereas \(30 \%\) are produced by \(A_{2}\) and \(20 \%\) come from \(A_{3} .\) a. Construct a tree diagram with first-generation branches corresponding to the three lines. Leading from each branch, draw one branch for rework (R) and another for no rework (N). Then enter appropriate probabilities on the branches. b. What is the probability that a randomly selected component came from \(A_{1}\) and needed rework? c. What is the probability that a randomly selected component needed rework?

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