Introductory Statistics (2nd Edition)
Introductory Statistics (2nd Edition)
2nd Edition
ISBN: 9780321978271
Author: Robert Gould, Colleen N. Ryan
Publisher: PEARSON
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Chapter 7, Problem 55SE

Thriving In June 2012, a Gallup Poll showed that when a sample of Americans were asked whether they were thriving, struggling, or suffering, about 54 % said they were thriving.

a. Assuming the sample size was 1000, how many in the sample said they were thriving?

b. Is the sample size large enough to apply the Central Limit Theorem? Explain. Assume the other conditions are met.

c. Find a 95 % confidence interval for the proportion that said they were thriving.

d. Find the width of the interval you found in part b by subtracting the lower limit from the upper limit. Round your answer to the nearest whole percent.

e. Now assume the sample size was 4000. How many would have said they were thriving?

f. Find a 95 % confidence interval for the proportion that said they were thriving using the numbers from part e.

g. What is the width of the interval you found in part f?

h. When the sample size is multiplied by 4 (as it was here, going from 1000 to 4000), is the interval width decreased by a factor of 4? In other words, is the interval for the larger sample size one-fourth 1 / 4 of the interval for the smaller sample size? If not, what is it divided by?

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Chapter 7 Solutions

Introductory Statistics (2nd Edition)

Ch. 7 - Finding a Random Sample (Example 5) You need to...Ch. 7 - Finding a Random Sample You need to select a...Ch. 7 - Random Sampling Assume your class has 30 students...Ch. 7 - Random Sampling with Coins Assume your class has...Ch. 7 - Questionnaire Response (Example 3) A teacher at a...Ch. 7 - Survey on Social Security A phone survey asked...Ch. 7 - Views on Capital Punishment In carrying out a...Ch. 7 - Views on Capital Punishment Use the data given in...Ch. 7 - Targets: Bias or Lack of Precision? a. If a...Ch. 7 - Targets: Bias or Lack of Precision, Again a. If a...Ch. 7 - Bias? Suppose that, when taking a random sample of...Ch. 7 - Unbiased Sample? Suppose you attend a school that...Ch. 7 - Proportion of Odd Digits A large collection of...Ch. 7 - Proportion of Odd Digits...Ch. 7 - Prob. 25SECh. 7 - Prob. 26SECh. 7 - ESP A Zener deck of cards has cards that show one...Ch. 7 - ESP Again In the graphs for Exercise 7.33, explain...Ch. 7 - Standard Error Which of the dotplots given in...Ch. 7 - Bias? Assuming that the true proportion of success...Ch. 7 - Fair Coin? One of the graphs shows the proportion...Ch. 7 - Far from Fair Which of the graphs in Exercise 7.37...Ch. 7 - What Is the Proportion of Seniors? (Example 5) A...Ch. 7 - Simulation From a very large (essentially...Ch. 7 - MMs (Example 5) Return to Exercise 7.25 and find...Ch. 7 - Random Letters Return to Exercise 7.26 and find...Ch. 7 - Jury Selection (Example 6) Juries should have the...Ch. 7 - Mercury in Freshwater Fish According to an article...Ch. 7 - The Oregon Bar Exam (Example 7) According to the...Ch. 7 - Feeding Vegans A survey of eating habits showed...Ch. 7 - Overweight Children The Ventura County Star (June...Ch. 7 - Living in Poverty The Ventura County Star article...Ch. 7 - Passing a Test by Guessing A true/false test has...Ch. 7 - Gender: Randomly Chosen? A large community college...Ch. 7 - Prob. 45SECh. 7 - Is Marriage Becoming Obsolete? When asked whether...Ch. 7 - East Germany According to a Gallup Poll taken in...Ch. 7 - View of Immigration In June 2012, a Gallup Poll...Ch. 7 - Voting A random sample of likely voters showed...Ch. 7 - Voting A random sample of likely voters showed...Ch. 7 - High School Diplomas (Example 8) In a simple...Ch. 7 - Diabetes In a simple random sample of 1200...Ch. 7 - Confidence in Public Schools A 2012 Gallup Poll...Ch. 7 - Confidence in the Military In June 2012, a Gallup...Ch. 7 - Thriving In June 2012, a Gallup Poll showed that...Ch. 7 - Benefits of Rich Class In May 2012, a Gallup Poll...Ch. 7 - Understanding the Meaning of Confidence Levels: 90...Ch. 7 - Understanding the Meaning of Confidence Levels: 80...Ch. 7 - Past Presidential Vote In the 1960 presidential...Ch. 7 - Human Cloning In a Gallup Poll, 441 of 507 adults...Ch. 7 - Do People Think Astrology Is Scientific? (Example...Ch. 7 - Do People Think the Sun Goes around the Earth? In...Ch. 7 - Good News on Jobs The Pew Research Center reports...Ch. 7 - Obesity In a 2013 Pew Poll, 36#37; of Republicans...Ch. 7 - Stressed Moms (Example 11, 12, 13, and 14) An...Ch. 7 - Gay Marriage According to the Pew Research Center,...Ch. 7 - Perry Preschool and Graduation from High School...Ch. 7 - Preschool: Just the Boys Refer to Exercise 7.77...Ch. 7 - Antibiotics for Malnutrition (Example 15) A study...Ch. 7 - Transfusions for Bleeding in the Stomach Should...Ch. 7 - Gender and Use of Turn Signals Statistics student...Ch. 7 - Diet Drug (Meridia) A randomized,...Ch. 7 - Drug for Nausea Ondansetron (Zofran) is a drug...Ch. 7 - Preschool: Just the Girls The Perry Preschool...Ch. 7 - Banning Super-Size Sugary Drinks A June 2012...Ch. 7 - Banning Smoking A July 2011 Roper Poll showed that...Ch. 7 - Sample Proportion A poll on a proposition showed...Ch. 7 - Sample Proportion A poll on a proposition showed...Ch. 7 - Margin of Error A poll on a proposition showed...Ch. 7 - Margin of Error A poll on a proposition showed...Ch. 7 - Prob. 81CRECh. 7 - Prob. 82CRECh. 7 - Dreaming in Color According to studies done in the...Ch. 7 - Hand Washing Ignaz Semmelweiss (1818-1865) was the...Ch. 7 - Romney vs. Santorum During the Republican primary...Ch. 7 - Sampling Error In March 2012, President Obama's...Ch. 7 - Young Women's Career Goals Are the career goals of...Ch. 7 - Young Men's Career Goals Are the career goals of...Ch. 7 - Voters Poll: Sample Size A polling agency wants to...Ch. 7 - Ratio of Sample Sizes Find the sample size...Ch. 7 - Criticize the Sampling Marco is interested in...Ch. 7 - Criticize the Sampling Maria opposes capital...Ch. 7 - Random Sampling? If you walked around your school...Ch. 7 - Biased Sample? You want to find the mean weight of...Ch. 7 - Bias? Suppose that, when taking a random sample of...Ch. 7 - Bias? Four women selected from a photo of 123 were...

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