Forming Conclusions. For each of Exercises 21–24, use the information about the confidence interval to answer the given question.
23. Feeling Tired. A USA Today report stated a survey of 22,000 high school students found that 39% of them reported being tired on most school days. The margin of error is less than 0.1 percentage point. Can we safely conclude that fewer than half of all students say they are tired on most days?
Want to see the full answer?
Check out a sample textbook solutionChapter 1 Solutions
Statistical Reasoning for Everyday Life Plus NEW MyLab Statistics with Pearson eText -- Title-Specific Access Card Package (5th Edition) (Bennett Science & Math Titles)
Additional Math Textbook Solutions
Introductory Statistics (10th Edition)
Fundamentals of Statistics (5th Edition)
EBK STATISTICAL TECHNIQUES IN BUSINESS
Statistical Techniques in Business and Economics
Introductory Statistics (2nd Edition)
Elementary Statistics: A Step By Step Approach
- The ACME computer company wanted to estimate the proportion of defective computersthat are produced by a particular factory. From information collected at the factory, they generate a confidence interval of (.024, .066).C. Complete this sentence (rewrite the sentence completely): The proportion of defective computers is most likely between ______________ and _______________. d. The minimum quality level for each is factory is less than 7% defective computers. According to the information provided above, is the company below the minimum?e. Suppose that you wanted to decrease the size of the confidence interval, how would you do it (without changing the standard deviation)?arrow_forward(e) What do you notice about the length of the confidence interval as the confidence level goes down? If you used a confidence level of 80%, would you expect the confidence interval to be longer or shorter than that of 85%? Run the program again to verify your answer.arrow_forwardDoes walking lower systolic blood pressure? Driving: x-bar = 125, s = 1, n = 32 Walking: x-bar = 119 miles, s = 1, n = 35 Construct a 95% confidence interval 1. What are the Degrees of Freedom on our data? 2. What is the Upper Limit of the Confidence Interval? 3. What is the Lower Limit of the Confidence Interval? 4. Based on your data, does walking lower systolic blood pressure?arrow_forward
- You wonder what percentage of students care about the language of instruction in choosing among universities to apply. To this end, you would like to construct a confidence interval for the proportion of students who care about instruction language. What is the minimum sample size you should use to ensure the length of a confidence interval to be less than or equal to 6% with 95% confidence? A ) 1058 B ) 1100 C ) 534 D ) 1068 E ) 267arrow_forwardA consumer group reports that a 90% confidence interval for the mean fat content of chicken nuggets from a fast-food restaurant is (14, 18). What is the mean fat content for the sample of 30 chicken nuggets or the point estimate that help make this confidence interval? A. 32 B. 16 C. 2arrow_forwardA researcher collected data on the annual salary of doctors in Illinois.He wishes to construct a confidence interval for the mean annual salary. Which of the following are true? I. A 98% confidence interval will have a greater chance of including the true mean salary than a 95% confidence interval.II. A 98% confidence interval will be narrower than a 95% confidence interval.III. A 98% confidence interval requires the researcher to take a larger sample. Choose the best answer below: A, II, III B. I C. III D. I, II E. IIarrow_forward
- Mental health. The General Social Survey asked the question: “For how many days during the past30 days was your mental health, which includes stress, depression, and problems with emotions, not good?”Based on responses from 1,151 US residents, the survey reported a 95% confidence interval of 3.40 to 4.24days in 2010.(a) Interpret this interval in context of the data.(b) What does “95% confident” mean? Explain in the context of the application.(c) Suppose the researchers think a 99% confidence level would be more appropriate for this interval. Willthis new interval be smaller or wider than the 95% confidence interval?(d) If a new survey were to be done with 500 Americans, do you think the standard error of the estimatebe larger, smaller, or about the same.arrow_forwardHard times in June 2010, a random poll 800 working men found that 9% had taking on a second job to help pay the bills. (www.careerbuilder.com) a) Estimate the true percentage of men that are taking on new jobs by constructing a 95% confidence interval. b) A pundit on a tv news sshow claimed that only 60% of working men had a second job. Use your confidence interval test whether his claim is plausible given the poll data.arrow_forwardRecent research commissioned by Vodafone suggests that older workers are the happiest employees (BBC News, July 21, 2008). The report documents that 70% of older workers in England feel fulfilled, compared with just 50% of younger workers. A demographer believes that an identical pattern does not exist in Asia. A survey of 120 older workers in Asia finds that 68 feel fulfilled. Give a 99% confidence interval for the proportion of workers in Asia who feel fulfilled at work. (Round to three decimal places.) Confidence Interval: toarrow_forward
- The university decided to conduct a satisfaction survey to assess the proportion of students likely to drop out. or change courses and, for that, a random sample of 900 students is selected. The result of this sample revealed that the number of students with a tendency to drop out or change courses was 50%. The 95% optimistic confidence interval for the proportion is approximately (Use ?? / 2 = ± 1.96) a)50% ± 3.11%.b) 50% ± 3.80%.c) 50% ± 1.00%.d) 50% ± 2.60%.e)50% ± 3.26%.arrow_forwardIt is always good to have as narrow a confidence interval as possible, because a C.I. is an estimate of a parameter, and a narrower C.I. is a more precise estimate. In lecture we learned three factors that affect the width of a C.I. With all that in mind, which C.I. below has the combination that would make it the NARROWEST out of all four options? (Hint: compare the answer options to each other two at a time, and do a process of elimination). A) A C.I. with n=55, 99% level of confidence, s2 = 5.0 (small variance) B) A C.I. with n=75, 99% level of confidence, s2 = 28.5 (large variance) C) A C.I. with n=75, 95% level of confidence, s2 = 5.0 (small variance) D) A C.I. with n=55, 95% level of confidence, s2 = 28.5 (large variance)arrow_forwardQ5. As we increase the confidence level from (e.g., 90% to 95%), the confidence interval length increases and the precision of our estimate decreases. TrueB. FalseC. Unsurearrow_forward
- MATLAB: An Introduction with ApplicationsStatisticsISBN:9781119256830Author:Amos GilatPublisher:John Wiley & Sons IncProbability and Statistics for Engineering and th...StatisticsISBN:9781305251809Author:Jay L. DevorePublisher:Cengage LearningStatistics for The Behavioral Sciences (MindTap C...StatisticsISBN:9781305504912Author:Frederick J Gravetter, Larry B. WallnauPublisher:Cengage Learning
- Elementary Statistics: Picturing the World (7th E...StatisticsISBN:9780134683416Author:Ron Larson, Betsy FarberPublisher:PEARSONThe Basic Practice of StatisticsStatisticsISBN:9781319042578Author:David S. Moore, William I. Notz, Michael A. FlignerPublisher:W. H. FreemanIntroduction to the Practice of StatisticsStatisticsISBN:9781319013387Author:David S. Moore, George P. McCabe, Bruce A. CraigPublisher:W. H. Freeman