APPLIED STAT.IN BUS.+ECONOMICS
6th Edition
ISBN: 9781259957598
Author: DOANE
Publisher: RENT MCG
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Textbook Question
Chapter 10.3, Problem 10SE
A special bumper was installed on selected vehicles in a large fleet. The dollar cost of body repairs was recorded for all vehicles that were involved in accidents over a 1-year period. Those with the special bumper are the test group and the other vehicles are the control group, shown below. Each “repair incident” is defined as an invoice (which might include more than one separate type of damage).
- (a) Construct a 90 percent confidence interval for the true difference of the means assuming equal variances. Show all work clearly. (b) Repeat, using the assumption of unequal variances with either Welch’s formula for d.f. or the quick rule for degrees of freedom. (c) Did the assumption about variances change the conclusion? (d) Construct separate confidence intervals for each mean. Do they overlap?
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In order to judge the effectiveness of an advertising campaign for a certain brand of pretzel, a company obtained a simple random sample of 95 convenience store receipts the week before the ad campaign began, and found that 28 of them showed a purchase of the pretzels. Another simple random sample of 65 receipts was taken the week after the ad campaign, and 33 of them showed a pretzel purchase. Construct a 98% confidence interval for the difference between the proportions of customers purchasing pretzels before and after the ad campaign. Interpret the results. A marketing manager claims that the proportion of customers who purchased pretzels did not change after the ad campaign. Does the confidence interval contradict this claim?
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Chapter 10 Solutions
APPLIED STAT.IN BUS.+ECONOMICS
Ch. 10.2 - Do a two-sample test for equality of means...Ch. 10.2 - Repeat the previous exercise, assuming unequal...Ch. 10.2 - Is there a difference in the average number of...Ch. 10.2 - Prob. 4SECh. 10.2 - Prob. 5SECh. 10.2 - Prob. 6SECh. 10.2 - Prob. 7SECh. 10.2 - On a random basis, Bob buys a small take-out...Ch. 10.2 - For a marketing class term project, Bob is...Ch. 10.3 - A special bumper was installed on selected...
Ch. 10.3 - In trials of an experimental internet-based method...Ch. 10.3 - Construct a 95 percent confidence interval for the...Ch. 10.4 - (a) At = .05, does the following sample show that...Ch. 10.4 - An experimental surgical procedure is being...Ch. 10.4 - Blue Box is testing a new half price on Tuesday...Ch. 10.4 - The U.S. governments Cash for Clunkers program...Ch. 10.4 - Prob. 17SECh. 10.4 - Below is a random sample of shoe sizes for 12...Ch. 10.4 - A newly installed automatic gate system was being...Ch. 10.5 - Calculate the test statistic and p-value for a...Ch. 10.5 - Prob. 21SECh. 10.5 - Prob. 22SECh. 10.5 - Prob. 23SECh. 10.5 - Prob. 24SECh. 10.5 - Prob. 25SECh. 10.5 - A survey of 100 mayonnaise purchasers showed that...Ch. 10.5 - Prob. 27SECh. 10.5 - Prob. 28SECh. 10.5 - When tested for compliance with Sarbanes-Oxley...Ch. 10.5 - Prob. 30SECh. 10.5 - From a telephone log, an executive finds that 36...Ch. 10.5 - Prob. 32SECh. 10.6 - The American Bankers Association reported that, in...Ch. 10.6 - A study showed that 36 of 72 cell phone users with...Ch. 10.6 - Prob. 35SECh. 10.7 - Which samples show unequal variances? Use = .10...Ch. 10.7 - Prob. 37SECh. 10.7 - Prob. 38SECh. 10.7 - A manufacturing process drills holes in sheet...Ch. 10.7 - Examine the data below showing the weights (in...Ch. 10 - (a) Explain why two samples from the same...Ch. 10 - (a) In a two-sample test of proportions, what is a...Ch. 10 - List the three cases for a test comparing two...Ch. 10 - Consider Case 1 (known variances) in the test...Ch. 10 - Consider Case 2 (unknown but equal variances) in...Ch. 10 - Consider Case 3 (unknown and unequal variances) in...Ch. 10 - Why is it a good idea to use a computer program...Ch. 10 - (a) Explain why the paired t test for dependent...Ch. 10 - Explain how a difference in means could be...Ch. 10 - (a) Why do we use an F test? (b) When two...Ch. 10 - (a) In an F test for two variances, explain how to...Ch. 10 - Prob. 41CECh. 10 - In an early home game, an NBA team made 66 of...Ch. 10 - Prob. 43CECh. 10 - A recent study found that 202 women held board...Ch. 10 - A study of the Fortune 100 board of director...Ch. 10 - Prob. 46CECh. 10 - How many full-page advertisements are found in a...Ch. 10 - eShopNet, an online clothing retailer, is testing...Ch. 10 - After John F. Kennedy Jr. was killed in an...Ch. 10 - A ski company in Vail owns two ski shops, one on...Ch. 10 - At a University of Colorado womens home basketball...Ch. 10 - A ski resort tracks the proportion of seasonal...Ch. 10 - Does a follow-up reminder increase the renewal...Ch. 10 - A study revealed that the 30-day readmission rate...Ch. 10 - In a marketing class, 44 student members of...Ch. 10 - In San Francisco, a sample of 3,200 wireless...Ch. 10 - Prob. 57CECh. 10 - Prob. 58CECh. 10 - Prob. 59CECh. 10 - Prob. 60CECh. 10 - Prob. 61CECh. 10 - Prob. 62CECh. 10 - In a 15-day survey of air pollution in two...Ch. 10 - Prob. 64CECh. 10 - Do male and female school superintendents earn the...Ch. 10 - The average take-out order size for Ashoka Curry...Ch. 10 - Cash withdrawals from a college credit union for a...Ch. 10 - In Mini Case 10.2, we found that the mean methane...Ch. 10 - A ski company in Vail owns two ski shops, one on...Ch. 10 - A ski company in Vail owns two ski shops, one on...Ch. 10 - Emergency room arrivals in a large hospital showed...Ch. 10 - Concerned about graffiti, mayors of nine suburban...Ch. 10 - A certain company will purchase the house of any...Ch. 10 - Nine homes are chosen at random from real estate...Ch. 10 - Prob. 75CECh. 10 - Prob. 76CECh. 10 - Prob. 77CECh. 10 - Is there a difference between the variance in ages...Ch. 10 - A survey of 100 mayonnaise purchasers showed that...Ch. 10 - A 20-minute consumer survey mailed to 500 adults...Ch. 10 - One group of accounting students used simulation...Ch. 10 - Advertisers fear that users of DVRs (digital video...Ch. 10 - In preliminary tests of a vaccine that may help...Ch. 10 - Prob. 84CECh. 10 - Male and female students in a finance class were...Ch. 10 - Prob. 86CECh. 10 - A retailer compared the frequency of customer...Ch. 10 - Streeling University surveyed a random sample of...Ch. 10 - The Fischer Theatre compared attendance at its...Ch. 10 - Random samples of tires being replaced by a car...Ch. 10 - Count the number of two-door vehicles among 50...Ch. 10 - Which statement is not correct? Explain. a. The...Ch. 10 - Match each statement to the correct property of an...Ch. 10 - Concerning confidence intervals, which statement...Ch. 10 - Prob. 4ERQCh. 10 - Prob. 5ERQCh. 10 - Prob. 6ERQCh. 10 - Prob. 7ERQCh. 10 - Prob. 8ERQCh. 10 - The process that produces Sonora Bars (a type of...Ch. 10 - Prob. 10ERQCh. 10 - Prob. 11ERQCh. 10 - Last month, 85 percent of the visitors to the...Ch. 10 - Weights of 12 randomly chosen Sonora Bars (a type...Ch. 10 - In a random sample of 200 Colorado residents, 150...Ch. 10 - Five students in a large lecture class compared...Ch. 10 - Prob. 16ERQCh. 10 - Prob. 17ERQ
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