Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 4: Q 33. (page 229)

Running red lights The sample described in Exercise 31produced a list of 5024licensed drivers. The investigators then chose an SRS of 880 of these drivers to answer questions about their driving habits. One question asked was: “Recalling the last ten traffic lights you drove through, how many of them were red when you entered the intersections?” Of the 880 respondents, 171admitted that at least one light had been red. A practical problem with this survey is that people may not give truthful answers. What is the likely direction of the bias: do you think more or fewer than 171 of the 880 respondents really ran a red light? Why?

Short Answer

Expert verified

We expect more than 171 respondents to admit that they ran a red light.

Step by step solution

01

Given information

A sample size of drivers, n=880

A practical problem with this survey is that people may not give truthful answers.

02

Concept

A simple random sample (SRS) of size n is made up of n people chosen from the population with an equal chance of being the sample that is actually chosen.

03

Explanation

There could have been a large number of persons that ran a red light. However, due to societal difficulties, most will not admit to running a red light. As a result, we predict more than 171 people to admit to running a red light.

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.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

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

Do placebos really work? Researchers in Japan conducted an experiment on 131 individuals who were extremely allergic to poison ivy. On one arm, each subject was rubbed with a poison ivy leaf and told the leaf was harmless. On the other arm, each subject was rubbed with a harmless leaf and told it was poison ivy. All the subjects developed a rash on the arm where the harmless leaf was rubbed. Of the

13subjects, 11 did not have any reaction to the real poison ivy leaf.

(a) What was the placebo in this experiment?

(b) Explain how the results of this study support the idea of a placebo effect.

Internet telephone calls You can use Voice over Internet Protocol (VoIP) to make long-distance

telephone calls over the Internet. How will the cost affect the use of this service? A university plans an experiment to find out. It will offer the service to all 350 students in one of its dormitories. Some students will pay a low flat rate. Others will pay higher rates at peak periods and very low rates off-peak. The university is interested in the amount and time of use and inthe effect on the congestion of the network.

Layoffs and “survivor guilt” Workers who survive a layoff of other employees at their location may suffer from “survivor guilt.” A study of survivor guilt and its effects used as subjects120students who were offered an opportunity to earn extra course credit by doing proofreading. Each subject worked in the same

cubicle as another student, who was an accomplice of the experimenters. At a break midway through the work, one of three things happened:

Treatment 1: The accomplice was told to leave; it was explained that this was because she performed poorly.

Treatment 2: It was explained that unforeseen circumstances meant there was only enough work for one person. By “chance,” the accomplice was chosen to

be laid off.

Treatment 3: Both students continued to work after the break.

The subjects’ work performance after the break was compared with performance before the break. Describe how you would randomly assign the

subjects to the treatments

(a) using slips of paper.

(b) using Table D.

(c) using technology.

Checking for bias Comment on each of the following as a potential sample survey question. Is the question clear? Is it slanted toward the desired response?

(a) Which of the following best represents your opinion on gun control?

1. The government should confiscate our guns.

2. We have the right to keep and bear arms.

(b) A freeze on nuclear weapons should be favored because it would begin a much-needed process to stop everyone in the world from building nuclear

weapons now and reduce the possibility of nuclear war in the future. Do you agree or disagree?

Stronger players A football coach hears that a new exercise program will increase upper-body strength better than lifting weights. He is eager to test this new program in the off-season with the players on his high school team. The coach decides to let his players choose which of the two treatments they will undergo

for three weeks—exercise or weight lifting. He will use the number of push-ups a player can do at the end of the experiment as the response variable.

(a) Which principle of experimental design does the coach’s plan violate? Explain how this violation could lead to confounding.

(b) Comment on the coach’s choice of response variable.
See all solutions

Recommended explanations on Math Textbooks

Probability and Statistics

Read Explanation

Statistics

Read Explanation

Mechanics Maths

Read Explanation

Theoretical and Mathematical Physics

Read Explanation

Geometry

Read Explanation

Pure Maths

Read Explanation
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.

Sign-up for free