Essentials of Statistics for Business and Economics, Loose-leaf Version
8th Edition
ISBN: 9781337114196
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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Chapter 11.2, Problem 21E
Many smartphones, especially those of the LTE-enabled persuasion, have earned a bad rap for exceptionally poor battery life. Battery life between charges for the Motorola Droid Razr Max averages 20 hours when the primary use is talk time and 7 hours when the primary use is Internet applications (The Wall Street Journal, March 7, 2012). Since 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 hours of use 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 hours of use is greater for the talk time application.
- b. What are the standard deviations of battery hours of use 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 and Economics, Loose-leaf Version
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 - Prob. 4ECh. 11.1 - Prob. 5ECh. 11.1 - Prob. 6ECh. 11.1 - Volatility of General Electric Stock. To analyze...Ch. 11.1 - Variability in Daily Change in Stock Price....Ch. 11.1 - Prob. 9ECh. 11.1 - Costco Customer Satisfaction. Consumer Reports...
Ch. 11.1 - Prob. 11ECh. 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 - 21. Many smartphones, especially those of the...Ch. 11.2 - Prob. 22ECh. 11 - 23. Because of staffing decisions, managers of the...Ch. 11 - Prob. 24SECh. 11 - Prob. 25SECh. 11 - Prob. 26SECh. 11 - Prob. 27SECh. 11 - Prob. 28SECh. 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 - Prob. 33SECh. 11 - Two new assembly methods are tested and the...
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