/*! 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 37 A rental car company offers two ... [FREE SOLUTION] | 91Ó°ÊÓ

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A rental car company offers two options when a car is rented. A renter can choose to pre-purchase gas or not and can also choose to rent a GPS device or not. Suppose that the events \(A=\) event that gas is pre-purchased \(B=\) event that a GPS is rented are independent with \(P(A)=0.20\) and \(P(B)=0.15\). a. Construct a hypothetical 1000 table with columns corresponding to whether or not gas is pre-purchased and rows corresponding to whether or not a GPS is rented. b. Use the table to find \(P(A \cup B)\). Give a long-run relative frequency interpretation of this probability.

Short Answer

Expert verified
In this problem, we have independent events \(A\) - pre-purchasing gas and \(B\) - renting a GPS device, with probabilities \(P(A)=0.20\) and \(P(B)=0.15\). We constructed a hypothetical table of 1000 cases presenting combinations of these events and calculated the probability of the union of events A and B as follows: \(P(A \cup B) = \frac{30 + 120 + 170}{1000} = \frac{320}{1000} = 0.32\) This means that in the long run, for 1000 car rentals, about 32% (or 320 out of 1000 times) the renter would either pre-purchase gas or rent a GPS device or both.

Step by step solution

01

Understanding the given information

We know that events \(A\) and \(B\) are independent, meaning that the occurrence of one event doesn't affect the occurrence of the other event. We are given the probabilities: \(P(A) = 0.20\) and \(P(B) = 0.15\). To calculate \(P(A \cup B)\) for independent events, we can use the following formula: \(P(A \cup B) = P(A) + P(B) - P(A)P(B)\)
02

Deriving probabilities from the given information

Since events A and B are independent, we can compute probabilities of their complements as follows: 1. Probability of not pre-purchasing gas: \(P(A') = 1 - P(A) = 1 - 0.20 = 0.80\) 2. Probability of not renting a GPS: \(P(B') = 1 - P(B) = 1 - 0.15 = 0.85\)
03

Constructing the table using the hypothetical 1000 cases

To construct the table, we will use the probabilities derived in Step 2 and multiply each with the hypothetical 1000 cases. The table will look like this: | | Gas Pre-Purchased (A) | Gas Not Pre-Purchased (A') | Total | |----------------|-----------------------|----------------------------|-------| | GPS Rented (B) | 30 | 120 | 150 | | No GPS (B') | 170 | 680 | 850 | | Total | 200 | 800 | 1000 | The values in the table are calculated using the probabilities and the hypothetical 1000 cases, e.g., -GPS rented (B) and gas pre-purchased (A): \(1000 \times P(A) \times P(B) = 1000 \times 0.20 \times 0.15 = 30\) -GPS rented (B) and gas not pre-purchased (A'): \(1000 \times P(A') \times P(B) = 1000 \times 0.80 \times 0.15 = 120\) -And other values are calculated in a similar manner.
04

Calculate the probability of the union of events A and B

Using the values from the table, we can calculate the probability of the union of events A and B as follows: \(P(A \cup B) = \frac{30 + 120 + 170}{1000} = \frac{320}{1000} = 0.32\) The long-run relative frequency interpretation of this probability is that, in the long run, for 1000 car rentals, about 32% (or 320 out of 1000 times) the renter would either pre-purchase gas or rent a GPS device or both.

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Key Concepts

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

Probability Theory
Probability theory is a branch of mathematics that helps us understand how likely events are to occur. It provides us with tools to quantify uncertainty and make informed predictions based on the likelihood of different outcomes.

There are some key concepts involved in probability theory:
  • **Probability Mass Function (PMF):** Deals with discrete random variables, where each possible outcome has an associated probability.
  • **Probability Density Functions (PDF):** Used for continuous random variables, showing distribution over a range.
  • **Events:** Outcomes or combinations of outcomes within a sample space.
  • **Sample Space:** The set of all possible outcomes.
In our exercise, we deal with two independent events: pre-purchasing gas and renting a GPS, where probabilities like \(P(A) = 0.20\) and \(P(B) = 0.15\) illustrate how often these events occur.
Long-Run Relative Frequency
Long-run relative frequency is a concept in probability that explains how often an event occurs over many trials or occurrences. It is the proportion of times that a particular event happens when an experiment is repeated a large number of times.

For example, in our rental car exercise, the probability of a union, \(P(A \cup B) = 0.32\), means that in the long run, about 32% of the time, either gas is pre-purchased, a GPS is rented, or both occur. In a setting of 1000 rentals, this probability suggests that 320 rentals would involve at least one of these actions.
  • This concept helps to demonstrate how probability works in real life.
  • It translates theoretical probabilities into expected occurrences over time.
Probability of Union
The probability of the union of two events, denoted \(P(A \cup B)\), refers to the chance of at least one of the events happening. The formula we often use for this calculation is:
  • \(P(A \cup B) = P(A) + P(B) - P(A)P(B)\)
This formula is especially useful when the two events A and B are independent. It helps avoid double counting the scenario where both events happen simultaneously.

In our scenario, they calculated \(P(A \cup B) = 0.32\), indicating that there's a 32% chance that either one or both events occur in a rental car situation. This probability tells us how likely it is to have either independent event, expanding our understanding of possible outcomes.
Complementary Events
Complementary events are pairs of outcomes where only one can occur at a time, and together they account for all possibilities. If the event is \(A\), then its complement is \(A'\), representing all outcomes not in \(A\).

Mathematically, the sum of an event's probability and its complement is always 1:
  • \(P(A) + P(A') = 1\)
In our exercise, we have:
  • \(P(A') = 1 - P(A) = 0.80\)
  • \(P(B') = 1 - P(B) = 0.85\)
Understanding complementary events helps determine the likelihood of both occurrence and non-occurrence, providing a complete picture of the situation's probabilities.

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Most popular questions from this chapter

In an article that appears on the website of the American Statistical Association, Carlton Gunn, a public defender in Seattle, Washington, wrote about how he uses statistics in his work as an attorney. He states: I personally have used statistics in trying to challenge the reliability of drug testing results. Suppose the chance of a mistake in the taking and processing of a urine sample for a drug test is just 1 in 100 . And your client has a "dirty" (i.e., positive) test result. Only a 1 in 100 chance that it could be wrong? Not necessarily. If the vast majority of all tests given say 99 in 100 -are truly clean, then you get one false dirty and one true dirty in every 100 tests, so that half of the dirty tests are false. Define the following events as \(T D=\) event that the test result is dirty \(T C=\) event that the test result is clean \(D=\) event that the person tested is actually dirty \(C=\) event that the person tested is actually clean a. Using the information in the quote, what are the values of $$ \text { i. } P(T D \mid D) $$ iii. \(P(C)\) $$ \text { ii. } P(T D \mid C) $$ iv. \(P(D)\) b. Use the probabilities from Part (a) to construct a hypothetical 1000 table. c. What is the value of \(P(T D)\) ? d. Use the information in the table to calculate the probability that a person is clean given that the test result is dirty, \(P(C \mid T D)\). Is this value consistent with the argument given in the quote? Explain.

Six people hope to be selected as a contestant on a TV game show. Two of these people are younger than 25 years old. Two of these six will be chosen at random to be on the show. a. What is the sample space for the chance experiment of selecting two of these people at random? (Hint: You can think of the people as being labeled \(\mathrm{A}, \mathrm{B}, \mathrm{C}, \mathrm{D}, \mathrm{E},\) and \(\mathrm{F}\). One possible selection of two people is \(\mathrm{A}\) and \(\mathrm{B}\). There are 14 other possible selections to consider.) b. Are the outcomes in the sample space equally likely? c. What is the probability that both the chosen contestants are younger than \(25 ?\) d. What is the probability that both the chosen contestants are not younger than \(25 ?\) e. What is the probability that one is younger than 25 and the other is not?

Airline tickets can be purchased online, by telephone, or by using a travel agent. Passengers who have a ticket sometimes don't show up for their flights. Suppose a person who purchased a ticket is selected at random. Consider the following events: \(O=\) event selected person purchased ticket online \(N=\) event selected person did not show up for flight Suppose \(P(O)=0.70, P(N)=0.07,\) and \(P(O \cap N)=0.04\) a. Are the events \(N\) and \(O\) independent? How can you tell? b. Construct a hypothetical 1000 table with columns corresponding to \(N\) and \(\operatorname{not} N\) and rows corresponding to \(O\) and \(\operatorname{not} O\). c. Use the table to find \(P(O \cup N)\). Give a relative frequency interpretation of this probability.

An online store offers two methods of shipping-regular ground service and an expedited 2 -day shipping. Customers may also choose whether or not to have the purchase gift wrapped. Suppose that the events \(E=\) event that the customer chooses expedited shipping \(G=\) event that the customer chooses gift wrap are independent with \(P(E)=0.26\) and \(P(G)=0.12\). a. Construct a hypothetical 1000 table with columns corresponding to whether or not expedited shipping was chosen and rows corresponding to whether or not gift wrap was selected. b. Use the information in the table to calculate \(P(E \cup G)\). Give a long- run relative frequency interpretation of this probability.

In a January 2016 Harris Poll, each of 2252 American adults was asked the following question: "If you had to choose, which ONE of the following sports would you say is your favorite?" ("Pro Football is Still America's Favorite Sport," www.theharrispoll.com/sports/Americas_Fav_Sport_2016. html, retrieved April 25,2017 ). Of the survey participants, \(33 \%\) chose pro football as their favorite sport. The report also included the following statement, "Adults with household incomes of \(\$ 75,000-<\$ 100,000(48 \%)\) are especially likely to name pro football as their favorite sport, while love of this particular game is especially low among those in \(\$ 100,000+$$ households \)(21 \%)\( Suppose that the percentages from this poll are representative of American adults in general. Consider the following events: \)F=\( event that a randomly selected American adult names pro football as his or her favorite sport \)L=\( event that a randomly selected American has a household income of \)\$ 75,000-<\$ 100,000\( \)H=\( event that a randomly selected American has a household income of \)\$ 100,000+$$ b. Are the events \(F\) and \(L\) mutually exclusive? Justify your answer. c. Are the events \(H\) and \(L\) mutually exclusive? Justify your answer. d. Are the events \(F\) and \(H\) independent? Justify your answer.

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