Applied Statistics in Business and Economics
5th Edition
ISBN: 9780077837303
Author: David Doane, Lori Seward Senior Instructor of Operations Management
Publisher: McGraw-Hill Education
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Chapter 10, Problem 75CE
a.
To determine
Check whether there is a difference in the defect rate between the two labs.
b.
To determine
Check whether the variances are equal or not.
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You collect data on coronavirus cases from a random sample of cities of similar sizes in cold climates and in warm climates and make the following table: (This data can be copied into Excel.)
You use this data to answer the research question: is the population average number of coronavirus cases different in warm cities and cold cities?
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A teacher is interested in assessing whether or not there is the same amount of variance in the scores of a particular type of test between male and female students. She believes that the variance for girls is higher than it is for boys. After grading the test she measures the following: In her class, 15 boys had a variance of 460 and 13 girls had a variance of 1,400.
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Suppose that in a certain year, it was reported that the variance in GMAT scores was 14,650. At a recent summit, a group of economics professors met to discuss the GMAT performance of undergraduate students majoring in economics. Some expected the variability in GMAT scores achieved by undergraduate economics students to be greater than the variability in GMAT scores of the general population of GMAT takers. However, others took the opposite view. Suppose the following are GMAT scores for 51 randomly selected undergraduate students majoring in economics.
345
749
427
767
336
777
663
451
787
454
711
544
453
330
718
462
585
658
550
576
773
572
629
591
481
574
510
628
532
411
702
640
686
608
510
509
617
576
546
392
512
573
794
690
581
527
329
451
666
377
720
(a)
Compute the mean, variance, and standard deviation of the GMAT scores for the 51 observations. (Round your answers to two decimal places.)
x= ( )
s2=( )
s= ( )
(b)
Develop hypotheses…
Chapter 10 Solutions
Applied Statistics in Business and 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 - In 2009, a sample of 200 in-store shoppers showed...Ch. 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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