/*! 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} Q 103. A probability teaser Suppose (as... [FREE SOLUTION] | 91影视

91影视

A probability teaser Suppose (as is roughly correct) that each child born is equally likely to be a boy or a girl and that the genders of successive children are independent. If we let BG mean that the older child is a boy and the younger child is a girl, then each of the combinations BB, BG, GB, and GG has a probability 0.25Ashley and Brianna each have two children.

(a) You know that at least one of Ashley鈥檚 children is a boy. What is the conditional probability that she has two boys?

(b) You know that Brianna鈥檚 older child is a boy. What is the conditional probability that she has two boys?

Short Answer

Expert verified

Part (a) 33.33%

Part (b) P (Two boy At least one boy) = 0.50

Step by step solution

01

Part (a) Step 1. Given Information

At least one of Ashley's children is suffering from the disease.

02

Part (a) Step 2. Concept

Condition probability: P(A|B)=P(AandB)P(B)

03

Part (a) Step 3. Calculation

Use the following formula to calculate the probability of a condition:

P(A|B)=P(AandB)P(B)

P(Twoboy||oldestisboy)=P(Twoboyandoldestisboy)P(oldestisboy)=P(Twoboy)P(oldestisboy)

P(Twoboys)=favourableoutcomespossibleoutcomes=14=0.25

P(Atleastoneboy)=favourableoutcomespossibleoutcomes=34=0.75

As a result, the conditional probability is:

P(Twoboy||Atleastoneboy)=P(Twoboys)P(Atleastoneboy)=0.250.75=130.3333=33.33%

As a result, the chances of her having two sons are 33.33%

04

Part (b) Step 1. Calculation

Condition probability: P(A/B)=P(AandB)P(B)

P(Twoboy||oldestisboy)=P(Twoboyandoldestisboy)P(oldestisboy)=P(Twoboy)P(oldestisboy)

P(Twoboys)=favourableoutcomespossibleoutcomes=14=0.25

P(oldestisboy)=favourableoutcomespossibleoutcomes=24=0.50

As a result, the conditional probability is: P(Twoboy||Atleastoneboy)=P(Twoboys)P(Atleastoneboy)=0.250.50=0.50

As a result, the conditional chance of her having two sons is 0.50

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Genetics Suppose a married man and woman both carry a gene for cystic fibrosis but don鈥檛 have the disease themselves. According to the laws of genetics, the probability that their first child will develop cystic fibrosis is 0.25

(a) Explain what this probability means.

(b) Why doesn鈥檛 this probability say that if the couple has 4 children, one of them is guaranteed to get cystic fibrosis?

Say in plain language what the eventAorBis.WhatisP(AorB)?

Recycling Do most teens recycle? To find out, an AP Statistics class asked an SRS of 100 students at their school whether they regularly recycle. How many students in the sample would need to say 鈥淵es鈥 to provide convincing evidence that more than half of the students at the school recycle? The Fathom dot plot below shows the results of taking 200 SRSs of 100 students from a population in which the true proportion who recycle is 0.50.

(a) Suppose 55 students in the class鈥檚 sample say 鈥淵es.鈥 Explain why this result does not give convincing evidence that more than half of the school鈥檚 students recycle.

(b) Suppose 63 students in the class鈥檚 sample say 鈥淵es.鈥 Explain why this result gives strong evidence that a majority of the school鈥檚 students recycle.

Liar, liar! Sometimes police use a lie detector (also known as a polygraph) to help determine whether a suspect is telling the truth. A lie detector test isn鈥檛 foolproof鈥攕ometimes it suggests that a person is lying when they鈥檙e actually telling the truth (a 鈥渇alse positive鈥). Other times, the test says that the suspect is being truthful when the person is actually lying (a 鈥渇alse negative鈥). For one brand of polygraph machine, the probability of a false positive is 0.08.
(a) Interpret this probability as a long-run relative frequency.
(b) Which is a more serious error in this case: a false positive or a false negative? Justify your answer.

Simulation blunders Explain what鈥檚 wrong with each of the following simulation designs.

(a) A roulette wheel has 38colored slots鈥38 red, 18 black, and 2green. To simulate one spin of the wheel, let numbers 00 to 18 represent red, 19 to 37

represent black, and 38 to 40 represent green.

(b) About 10% of U.S. adults are left-handed. To simulate randomly selecting one adult at a time until you find a left-hander, use two digits. Let 01 to 10 represent being left-handed and 11 to 00 represent being right-handed. Move across a row in Table D, two digits at a time, skipping any numbers that have already appeared, until you find a number between 01 and 10. Record the number of people selected.

See all solutions

Recommended explanations on Math Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.