MYLAB STATISTICS: ELEMENTARY STATISTICS
7th Edition
ISBN: 9780135901021
Author: Larson
Publisher: PEARSON EDUCATION (COLLEGE)
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Textbook Question
Chapter 8.3, Problem 18E
Testing the Difference Between Two Means In Exercises 9–20, (a) identify the claim and state H0 and Ha, (b) find the critical value(s) and identify the rejection region(s), (c) calculate
18. Pass Completion Percentages The pass completion percentages of 10 college football quarterbacks for their freshman and sophomore seasons are shown in the table below. At α = 0.10, is there enough evidence to support the claim that the pass completion percentages have changed? (Source: Sports Reference, LLC)
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A case-control (or retrospective) study was conducted to investigate a relationship between the colors of helmets worn by motorcycle drivers and whether they are injured or killed in a crash. Results are given in the accompanying table. Using a 0.01
significance level, test the claim that injuries are independent of helmet color.
Color of Helmet
Black
White
Yellow
Red
Blue
Controls (not injured)
499
373
32
159
79
Cases (injured
221
108
8
66
38
or killed)
Click here to view the chi-square distribution table.
Chi-square distribution table
Area to the Right of the Critical Value
Degrees of
Freedom
0.995
0.99
0.975
0.95
0.90
0.10
0.05
0.025
0.01
0.005
C. Ho: Injuries and neimet color are dependent
H₁: Injuries and helmet color are independent
D. Ho: Whether a crash occurs and helmet color are dependent
1
0.001
0.004
0.016
2.706
3.841
5.024
6.635
7.879
2
0.010
0.020
0.051
0.103
0.211
4.605
5.991
7.378
9.210
10.597
3
0.072
0.115
0.216
0.352
0.584
6.251
7.815
9.348
11.345
12.838
4
0.207
0.297…
Conduct the hypothesis test and provide the test statistic and the critical value, and state the conclusion.
A person drilled a hole in a die and filled it with a lead weight, then proceeded to roll it 200 times. Here are the observed frequencies for the outcomes of 1, 2, 3, 4, 5, and 6, respectively: 28, 32, 46, 39, 29, 26. Use a 0.025 significance level to test the
claim that the outcomes are not equally likely. Does it appear that the loaded die behaves differently than a fair die?
Click here to view the chi-square distribution table.
The test statistic is
(Round to three decimal places as needed.)
Chi-square distribution table
Area to the Right of the Critical Value
Degrees of
Freedom
0.995
0.99
0.975
0.95
0.90
0.10
0.05
0.025
0.01
0.005
1
0.001
0.004
0.016
2.706
3.841
5.024
6.635
2
0.010
0.020
0.051
0.103
0.211
4.605
5.991
7.378
9.210
7.879
10.597
3
0.072
0.115
0.216
0.352
0.584
6.251
7.815
9.348
11.345 12.838
4
0.207
0.297
0.484
0.711
1.064
7.779
9.488
11.143
13.277 14.860
5…
The online clothing retailer e-Parel is conducting a study to estimate the average size of the orders placed by visitors to its website. The project manager desires a $60 bound on the error of estimation at 90% confidence. The population standard deviation is unknown, and a “best guess” of $175 is used as the planning value for σ.
Use the Distributions tool to help you answer the questions that follow.
0123
Select a Distribution
The z-value for a 90% confidence interval of the population mean is .
In order to satisfy the requirement of a $60 bound on the error of estimation, a sample size no smaller than is needed.
Chapter 8 Solutions
MYLAB STATISTICS: ELEMENTARY STATISTICS
Ch. 8.1 - Classify each pair of samples as independent or...Ch. 8.1 - A survey indicates that the mean annual wages for...Ch. 8.1 - A travel agency claims that the average daily cost...Ch. 8.1 - What is the difference between two samples that...Ch. 8.1 - Explain how to perform a two-sample z-test for the...Ch. 8.1 - Describe another way you can perform a hypothesis...Ch. 8.1 - What conditions are necessary in order to use the...Ch. 8.1 - Prob. 5ECh. 8.1 - Prob. 6ECh. 8.1 - Independent and Dependent Samples In Exercises 58,...
Ch. 8.1 - Prob. 8ECh. 8.1 - In Exercises 9 and 10, use the TI-H4 Plus display...Ch. 8.1 - Prob. 10ECh. 8.1 - Prob. 11ECh. 8.1 - In Exercises 1114, test the claim about the...Ch. 8.1 - In Exercises 1114, test the claim about the...Ch. 8.1 - Prob. 14ECh. 8.1 - Testing the Difference Between Two Means In...Ch. 8.1 - Testing the Difference Between Two Means In...Ch. 8.1 - Prob. 17ECh. 8.1 - Prob. 18ECh. 8.1 - Prob. 19ECh. 8.1 - Testing the Difference Between Two Means In...Ch. 8.1 - Testing the Difference Between Two Means In...Ch. 8.1 - Prob. 22ECh. 8.1 - Prob. 23ECh. 8.1 - Prob. 24ECh. 8.1 - Prob. 25ECh. 8.1 - Getting at the Concept Explain why the null...Ch. 8.1 - Testing a Difference Other Than Zero Sometimes a...Ch. 8.1 - Testing a Difference Other Than Zero Sometimes a...Ch. 8.1 - Prob. 29ECh. 8.1 - Architect Salaries Construct a 99% confidence...Ch. 8.2 - The annual earnings of 25 people with a high...Ch. 8.2 - A manufacturer claims that the mean driving cost...Ch. 8.2 - What conditions are necessary in order to use the...Ch. 8.2 - Explain how to perform a two-sample t-test for the...Ch. 8.2 - Prob. 3ECh. 8.2 - Prob. 4ECh. 8.2 - Prob. 5ECh. 8.2 - Prob. 6ECh. 8.2 - In Exercises 38, use Table 5 in Appendix B to find...Ch. 8.2 - Prob. 8ECh. 8.2 - In Exercises 912, test the claim about the...Ch. 8.2 - Prob. 10ECh. 8.2 - Prob. 11ECh. 8.2 - In Exercises 912, test the claim about the...Ch. 8.2 - Testing the Difference Between Two Means in...Ch. 8.2 - Testing the Difference Between Two Means in...Ch. 8.2 - Testing the Difference Between Two Means in...Ch. 8.2 - Testing the Difference Between Two Means in...Ch. 8.2 - Prob. 17ECh. 8.2 - Prob. 18ECh. 8.2 - Prob. 19ECh. 8.2 - Testing the Difference Between Two Means in...Ch. 8.2 - Testing the Difference Between Two Means in...Ch. 8.2 - Testing the Difference Between Two Means in...Ch. 8.2 - Constructing Confidence Intervals for 1 2 When...Ch. 8.2 - Constructing Confidence Intervals for 1 2 When...Ch. 8.2 - Constructing Confidence Intervals for 1 2 When...Ch. 8.2 - Prob. 26ECh. 8.2 - How Protein Affects Weight Gain in Overeaters In a...Ch. 8.2 - Prob. 2CSCh. 8.2 - How Protein Affects Weight Gain in Overeaters In a...Ch. 8.2 - Prob. 4CSCh. 8.2 - Prob. 5CSCh. 8.3 - A shoe manufacturer claims that athletes can...Ch. 8.3 - Prob. 2TYCh. 8.3 - Prob. 1ECh. 8.3 - Prob. 2ECh. 8.3 - Prob. 3ECh. 8.3 - Prob. 4ECh. 8.3 - Prob. 5ECh. 8.3 - Prob. 6ECh. 8.3 - Prob. 7ECh. 8.3 - Prob. 8ECh. 8.3 - Prob. 9ECh. 8.3 - Testing the Difference Between Two Means In...Ch. 8.3 - Prob. 11ECh. 8.3 - Prob. 12ECh. 8.3 - Prob. 13ECh. 8.3 - Testing the Difference Between Two Means In...Ch. 8.3 - Prob. 15ECh. 8.3 - Prob. 16ECh. 8.3 - Testing the Difference Between Two Means In...Ch. 8.3 - Testing the Difference Between Two Means In...Ch. 8.3 - Testing the Difference Between Two Means In...Ch. 8.3 - Prob. 20ECh. 8.3 - Prob. 21ECh. 8.3 - Prob. 22ECh. 8.3 - Prob. 23ECh. 8.3 - Prob. 24ECh. 8.4 - Consider the results of the study discussed on...Ch. 8.4 - Prob. 2TYCh. 8.4 - What conditions are necessary in order to use the...Ch. 8.4 - Explain how to perform a two-sample z-test for the...Ch. 8.4 - In Exercises 36, determine whether a normal...Ch. 8.4 - Prob. 4ECh. 8.4 - Prob. 5ECh. 8.4 - In Exercises 36, determine whether a normal...Ch. 8.4 - Prob. 7ECh. 8.4 - Testing the Difference Between Two Proportions In...Ch. 8.4 - Prob. 9ECh. 8.4 - Prob. 10ECh. 8.4 - Prob. 11ECh. 8.4 - Testing the Difference Between Two Proportions In...Ch. 8.4 - Prob. 13ECh. 8.4 - Prob. 14ECh. 8.4 - Intermarriages In Exercises 1318, use the figure,...Ch. 8.4 - Prob. 16ECh. 8.4 - Prob. 17ECh. 8.4 - Intermarriages In Exercises 1318, use the figure,...Ch. 8.4 - Prob. 19ECh. 8.4 - Prob. 20ECh. 8.4 - Prob. 21ECh. 8.4 - U.S. Workforce In Exercises 1922, use the figure...Ch. 8.4 - Prob. 23ECh. 8.4 - Prob. 24ECh. 8.4 - Prob. 25ECh. 8.4 - Prob. 26ECh. 8 - Uses Hypothesis Testing with Two Samples...Ch. 8 - Medical research often involves blind and...Ch. 8 - Prob. 8.1.1RECh. 8 - Prob. 8.1.2RECh. 8 - Sample 1: The fuel efficiencies of 20 sports...Ch. 8 - Prob. 8.1.4RECh. 8 - Prob. 8.1.5RECh. 8 - In Exercises 58, test the claim about the...Ch. 8 - Prob. 8.1.7RECh. 8 - In Exercises 58, test the claim about the...Ch. 8 - In Exercises 9 and 10, (a) identify the claim and...Ch. 8 - Prob. 8.1.10RECh. 8 - Prob. 8.2.11RECh. 8 - Prob. 8.2.12RECh. 8 - Prob. 8.2.13RECh. 8 - Prob. 8.2.14RECh. 8 - Prob. 8.2.15RECh. 8 - Prob. 8.2.16RECh. 8 - Prob. 8.2.17RECh. 8 - Prob. 8.2.18RECh. 8 - Prob. 8.3.19RECh. 8 - In Exercises 1922, test the claim about the mean...Ch. 8 - Prob. 8.3.21RECh. 8 - Prob. 8.3.22RECh. 8 - Prob. 8.3.23RECh. 8 - In Exercises 23 and 24, (a) identify the claim and...Ch. 8 - Prob. 8.4.25RECh. 8 - Prob. 8.4.26RECh. 8 - Prob. 8.4.27RECh. 8 - Prob. 8.4.28RECh. 8 - Prob. 8.4.29RECh. 8 - Prob. 8.4.30RECh. 8 - Prob. 1CQCh. 8 - Prob. 2CQCh. 8 - Prob. 3CQCh. 8 - Prob. 4CQCh. 8 - Take this test as you would take a test in class....Ch. 8 - Prob. 2CTCh. 8 - A physical therapist suggests that soft tissue...Ch. 8 - Take this test as you would take a test in class....Ch. 8 - The U.S. Department of Health Human Services...Ch. 8 - Prob. 2RSRDCh. 8 - Prob. 3RSRDCh. 8 - Prob. 4RSRDCh. 8 - Prob. 1TCh. 8 - Prob. 2TCh. 8 - Prob. 3TCh. 8 - Prob. 4TCh. 8 - Prob. 5TCh. 8 - Prob. 1CRCh. 8 - Prob. 2CRCh. 8 - Prob. 3CRCh. 8 - Prob. 4CRCh. 8 - In Exercises 36, construct the indicated...Ch. 8 - In Exercises 36, construct the indicated...Ch. 8 - In Exercises 710, the statement represents a...Ch. 8 - In Exercises 710, the statement represents a...Ch. 8 - In Exercises 710, the statement represents a...Ch. 8 - In Exercises 710, the statement represents a...Ch. 8 - Prob. 11CRCh. 8 - Prob. 12CRCh. 8 - Prob. 13CRCh. 8 - Prob. 14CRCh. 8 - Prob. 15CRCh. 8 - Prob. 16CRCh. 8 - A researcher claims that 5% of people who wear...
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