An Introduction to Statistical Methods and Data Analysis
7th Edition
ISBN: 9781305269477
Author: R. Lyman Ott, Micheal T. Longnecker
Publisher: Cengage Learning
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Chapter 6.9, Problem 6E
The Department of Natural Resources (DNR) received a complaint from recreational fishermen that a community was releasing sewage into the river where they fished. These types of releases lower the level of dissolved oxygen in the river and hence cause damage to the fish residing in the river. An inspector from the DNR designs a study to investigate the fishermen’s claim. Fifteen water samples are selected at locations on the river upstream from the community and fifteen samples are selected downstream from the community. The dissolved oxygen readings in parts per million (ppm) are given in the following table.
- a. In order for the discharge to have an impact on fish health, there needs to be at least an .5 ppm reduction in the dissolved oxygen. Do the data provide sufficient evidence that there is a large enough reduction in the mean dissolved oxygen between the upstream and downstream water in the river to impact the health of the fish? Use α = .01.
- b. Do the required conditions to use the test in part (a) appear to be valid?
- c. What is the level of significance of the test in part (a)?
- d. Estimate the size of the difference in the mean dissolved oxygen readings for the two locations on the river using a 99% confidence interval.
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Students have asked these similar questions
Periodically, the county Water Department tests the drinking water of homeowners for contaminants
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To access the complete data set, click the link for your preferred software format:
Excel Minitab JMP SPSS TI R Mac-TXT PC-TXT CSV CrunchIt!
Find the mean E. coli level.
Mean E.coli level (rounded to two decimal places)
per 100 ml
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Chapter 6 Solutions
An Introduction to Statistical Methods and Data Analysis
Ch. 6.9 - Refer to the oil-spill case study.
What are the...Ch. 6.9 - For each of the situations, set up the rejection...Ch. 6.9 - Conduct a test of H0 : μ1 μ2 – 2.3 versus Ha : μ1...Ch. 6.9 - In an effort to link cold environments with...Ch. 6.9 - The Department of Natural Resources (DNR) received...Ch. 6.9 - An industrial engineer conjectures that a major...Ch. 6.9 - The number of households currently receiving a...Ch. 6.9 - Prob. 9ECh. 6.9 - Refer to Exercise 6.11. There appears to be a...Ch. 6.9 - A firm has a generous but rather complicated...
Ch. 6.9 - Prob. 14ECh. 6.9 - Random samples of size n1 = 8 and n2 = 8 were...Ch. 6.9 - Prob. 16ECh. 6.9 - Prob. 17ECh. 6.9 - The paper Serum Beta-2-Microglobulin (SB2M) in...Ch. 6.9 - Prob. 19ECh. 6.9 - Prob. 20ECh. 6.9 - Prob. 21ECh. 6.9 - Prob. 22ECh. 6.9 - A random sample of eight pairs of twins was...Ch. 6.9 - Refer to the data of Exercise 6.11. A potential...Ch. 6.9 - Researchers are studying two existing coatings...Ch. 6.9 - Prob. 27ECh. 6.9 - The paper “Effect of Long-Term Blood Pressure...Ch. 6.9 - A study was designed to measure the effect of home...Ch. 6.9 - Prob. 30ECh. 6.9 - A random sample of eight pairs of twins were...Ch. 6.9 - Refer to Exercise 6.31. a. What is the level of...Ch. 6.9 - Use the level and power values for the paired t...Ch. 6.9 - Use the level and power values for the paired t...Ch. 6.9 - A study was conducted to determine whether...Ch. 6.9 - The effect of Benzedrine on the heart rate of dogs...Ch. 6.9 - Prob. 37E
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