/*! 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. T8.4 Many television viewers express ... [FREE SOLUTION] | 91影视

91影视

Log out

Learning Materials

Features

Discover

Chapter 8: Q. T8.4 (page 549)

Many television viewers express doubts about the validity of certain commercials. In an attempt to answer their critics, Timex Group USA wishes to estimate the true proportion p of all consumers who believe what is shown in Timex television commercials. What is the smallest number of consumers that Timex can survey to guarantee a margin of error of 0.05or less at a 99%confidence level?

a. 550

b. 600

c. 650

d. 700

e. 750

Short Answer

Expert verified

The required smallest number of consumers is 600

The correct option is(b)

Step by step solution

01

Given information

Confidence level =99%

Margin of error(E)=0.05

02

The objective is to find out the smallest number of consumers to have the margin of error at most 0.05at 99%the confidence level.

We know,

The formula to compute the sample size is:

n=p^(1-p^)z伪2E2

There is no information about p^provided here.

Thus, assume is to be 0.50

According to the standard norma table, the value of z伪2corresponding to99%the confidence level is 2.576

The sample size is calculated as follows:

n=p^(1-p^)z伪2E2=0.50(1-0.50)2.5760.052=664

The smallest number of consumers is 600

Therefore, the correct option is(b)

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

One reason for using a t distribution instead of the standard Normal distribution to find critical values when calculating a level C confidence interval for a population mean is that

a. zcan be used only for large samples.

b. zrequires that you know the population standard deviation 蟽.

c. z requires that you can regard your data as an SRS from the population.

d. z requires that the sample size is less than 10% of the population size.

e. a z critical value will lead to a wider interval than a t critical value.

Power lines and cancer Does living near power lines cause leukemia in

children? The National Cancer Institute spent 5years and $5million gathering data on this question. The researchers compared 638children who had leukemia with 620who did not. They went into the homes and measured the magnetic fields in children鈥檚 bedrooms, in other rooms, and at the front door. They recorded facts about power lines near the family home and also near the mother鈥檚 residence when she was pregnant. Result: No association between leukemia and exposure to magnetic fields of the kind produced by power lines was found.

a. Was this an observational study or an experiment? Justify your answer.

b. Does this study prove that living near power lines doesn鈥檛 cause cancer? Explain your answer.

Scientists collect data on the blood cholesterol levels (milligrams per deciliter of blood) of a random sample of 24laboratory rats. A 95%confidence interval for the mean blood cholesterol level 渭is 80.2to 89.8. Which of the following would cause the most worry about the validity of this interval?

a. There is a clear outlier in the data.

b. A stem plot of the data shows a mild right skew.

c. You do not know the population standard deviation 蟽.

d. The population distribution is not exactly Normal.

e. None of these are a problem when using a t interval.

More Oranges:The gardener in the previous exercise randomly selects 20

mandarin oranges from the tree and counts the number of seeds in each orange. Here are the data:

a. Graph the data using a dot plot.

b. Based on your graph, is it plausible that the number of seeds from oranges on this tree follows a distribution that is approximately Normal? Explain your answer.

Suppose we want a 90% confidence interval for the average amount spent on books by freshmen in their first year at a major university. The interval is to have a margin of error of \(2. Based on last year鈥檚 book sales, we estimate that the standard deviation of the amount spent will be close to \)30. The number of observations required is closest to

(a) 25. (b) 30. (c) 608. (d) 609. (e) 865.
See all solutions

Recommended explanations on Math Textbooks

Discrete Mathematics

Read Explanation

Mechanics Maths

Read Explanation

Calculus

Read Explanation

Logic and Functions

Read Explanation

Statistics

Read Explanation

Probability and Statistics

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.