Introduction to Statistics and Data Analysis
5th Edition
ISBN: 9781305115347
Author: Roxy Peck; Chris Olsen; Jay L. Devore
Publisher: Brooks Cole
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Chapter 15.3, Problem 26E
To determine
Check whether the data provide any evidence that the mean fire-ant abundance is equal in all the conditions at 0.05 level of significance.
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Kava is a beverage or extract that is made from Piper methysticum, a plant native to the western Pacific islands. Suppose that,
in a randomized comparative experiment to determine if taking kava daily can reduce insomnia, a group of participants with
insomnia were randomly assigned to take kava (treatment group) or a placebo (control group). After six weeks, the
participants were interviewed to see if they experienced a decrease in insomnia. The table shows the results from the sample.
The counts are the number of people in each group who experienced a decrease in insomnia.
Group
Description
Population
proportion
Sample size Sample count
Sample proportion
1
Treatment (kava)
P1
n₁ = 402
x1 = 213
P₁ = 0.5299
2 Control (placebo)
P2
n₂ = 521
x₂ = 121
P2 = 0.2322
Compute the standard error estimate, SE, of the difference in the sample proportions. Give your answer to at least four
decimal places.
0.0438
SE =
Incorrect
Determine the value of the two-sample z-statistic for the difference in…
In the article “The Eastern Cottonmouth (Agkistrodon piscivorus) at the Northern Edge of Its Range” (Journal of Herpetology, Vol. 29, No. 3, pp. 391–398), Blem and Blem examined the reproductive characteristics of the eastern cottonmouth, a once widely distributed snake whose numbers have decreased recently due to encroachment by humans. A simple random sample of 44 female cottonmouths yielded a sample mean of ??̅ = 7.6 young per litter. Assume σ = 2.4. a. Is the sample mean likely to equal μ exactly? Explain your answer b. Find the 95% Confidence Interval. c. How large a sample would be needed to get at 99% confidence interval with a margin of error of just 0.1?
Social psychologists at the University of California at Berkeley wanted to study the effect that staring at drivers would have on driver behavior (Ellsworth, Carlsmith, and Henson, 1972). In a randomized experiment, the researchers either stared or did not stare at the drivers of automobiles stopped at a campus stop sign. The researchers timed how long it took each driver to proceed from the stop sign to a mark on the other side of the intersection. Suppose that the random sample of crossing times, in seconds, gave the following output:
Group N Mean StDev
No Stare 14 6.63 1.360
Stare 13 5.59 0.822
Construct a 95% confidence interval for the difference in stop times.
Chapter 15 Solutions
Introduction to Statistics and Data Analysis
Ch. 15.1 - Give as much information as you can about the...Ch. 15.1 - Prob. 2ECh. 15.1 - Employees of a state university system can choose...Ch. 15.1 - The accompanying summary statistics for a measure...Ch. 15.1 - The authors of the paper Age and Violent Content...Ch. 15.1 - The paper referenced in the previous exercise also...Ch. 15.1 - The Paper Womens and Mens Eating Behavior...Ch. 15.1 - Can use of an online plagiarism-detection system...Ch. 15.1 - The experiment described in Example 15.4 also gave...Ch. 15.1 - Prob. 10E
Ch. 15.1 - Prob. 11ECh. 15.1 - Prob. 12ECh. 15.1 - In an experiment to investigate the performance of...Ch. 15.2 - Leaf surface area is an important variable in...Ch. 15.2 - Prob. 15ECh. 15.2 - Prob. 16ECh. 15.2 - Prob. 17ECh. 15.2 - The paper referenced in Exercise 15.5 described an...Ch. 15.2 - Prob. 19ECh. 15.2 - The accompanying data resulted from a flammability...Ch. 15.2 - Do lizards play a role in spreading plant seeds?...Ch. 15.2 - Samples of six different brands of diet or...Ch. 15.3 - A particular county employs three assessors who...Ch. 15.3 - The accompanying display is a partially completed...Ch. 15.3 - With the use of biofuels increasing, investigators...Ch. 15.3 - Prob. 26ECh. 15.3 - Prob. 27ECh. 15.3 - Prob. 28ECh. 15.4 - Prob. 29ECh. 15.4 - The paper Feedback Enhances the Positive Effects...Ch. 15.4 - The following graphs appear in the paper Which...Ch. 15.4 - The behavior of undergraduate students when...Ch. 15.4 - Prob. 33ECh. 15.4 - The following partially completed ANOVA table...Ch. 15.4 - Prob. 35ECh. 15.4 - Prob. 36ECh. 15.4 - Prob. 37ECh. 15 - Suppose that a random sample or size n = 5 was...Ch. 15 - Parents are frequently concerned when their child...Ch. 15 - Prob. 40CRCh. 15 - Consider the accompanying data on plant growth...Ch. 15 - Prob. 42CRCh. 15 - Prob. 43CRCh. 15 - Prob. 44CRCh. 15 - Prob. 45CRCh. 15 - Prob. 46CRCh. 15 - Prob. 47CRCh. 15 - Prob. 48CRCh. 15 - Prob. 49CR
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