Essentials Of Statistics For Business & Economics
9th Edition
ISBN: 9780357045435
Author: David R. Anderson, Dennis J. Sweeney, Thomas A. Williams, Jeffrey D. Camm, James J. Cochran
Publisher: South-Western College Pub
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Textbook Question
Chapter 11.2, Problem 21E
Smartphone Battery Life. Battery life is an important issue for many smartphone owners. Public health studies have examined “low-battery anxiety” and acute anxiety called nomophobia that results when a smartphone user’s phone battery charge runs low and then dies (Wall Street Journal, https://www.wsj.com/articles/your-phone-is-almost-out-of-battery-remain-calm-call-a-doctor-1525449283). Battery life between charges for the Samsung Galaxy S9 averages 31 hours when the primary use is talk time and 10 hours when the primary use is Internet applications. Because the mean hours for talk time usage is greater than the mean hours for Internet usage, the question was raised as to whether the variance in hours of usage is also greater when the primary use is talk time. Sample data showing battery life between charges for the two applications follows.
- a. Formulate hypotheses about the two population variances that can be used to determine if the population variance in battery life is greater for the talk time application.
- b. What are the standard deviations of battery life for the two samples?
- c. Conduct the hypothesis test and compute the p-value. Using a .05 level of significance, what is your conclusion?
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Chapter 11 Solutions
Essentials Of Statistics For Business & Economics
Ch. 11.1 - 1. Find the following chi-square distribution...Ch. 11.1 - Prob. 2ECh. 11.1 - A sample of 16 items provides a sample standard...Ch. 11.1 - Package Delivery by Drones. Amazon.com is testing...Ch. 11.1 - College Basketball Coaches’ Salaries. In 2018,...Ch. 11.1 - Volatility of General Electric Stock. To analyze...Ch. 11.1 - Halloween Spending. In 2017, Americans spent a...Ch. 11.1 - Variability in Daily Change in Stock Price....Ch. 11.1 - Aerospace Part Manufacturing. The competitive...Ch. 11.1 - Costco Customer Satisfaction. Consumer Reports...
Ch. 11.1 - Variability in GMAT Scores. In 2016, the Graduate...Ch. 11.1 - Vehicle Ownership by Fortune Magazine Subscribers....Ch. 11.2 - Find the following F distribution values from...Ch. 11.2 - A sample of 16 items from population 1 has a...Ch. 11.2 - Prob. 15ECh. 11.2 - Comparing Risk of Mutual Funds. Investors commonly...Ch. 11.2 - Repair Costs as Automobiles Age. In its 2016 Auto...Ch. 11.2 - Prob. 18ECh. 11.2 - Prob. 19ECh. 11.2 - Prob. 20ECh. 11.2 - Smartphone Battery Life. Battery life is an...Ch. 11.2 - Prob. 22ECh. 11 - 23. Because of staffing decisions, managers of the...Ch. 11 - Prob. 24SECh. 11 - Business Travel Costs. According to the 2017...Ch. 11 - Manufacture of Ball Bearings. Ball bearing...Ch. 11 - Count Chocula Cereal. Filling boxes with...Ch. 11 - OrderUp Food Delivery. OrderUp is a service that...Ch. 11 - Daily Patient Volume at Dental Clinic. A sample of...Ch. 11 - A sample standard deviation for the number of...Ch. 11 - Golf Scores. Is there any difference in the...Ch. 11 - Grade Point Average Comparison. The grade point...Ch. 11 - Weekly Cost Reporting. Stable cost reporting in a...Ch. 11 - Lean Process Improvement at the New York City Food...Ch. 11 - An Air Force introductory course in electronics...Ch. 11 - Meticulous Drill Reamer (MDR) specializes in...
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