Elementary Statistics: Picturing the World (7th Edition)
Elementary Statistics: Picturing the World (7th Edition)
7th Edition
ISBN: 9780134683416
Author: Ron Larson, Betsy Farber
Publisher: PEARSON
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Chapter 8, Problem 1UA

Uses

Hypothesis Testing with Two Samples Hypothesis testing enables you to determine whether differences in samples indicate actual differences in populations or are merely due to sampling error. For instance, a study conducted on about 1400 American children in a variety of settings compared the behavior of the children who attended day care with the behavior of those who stayed home. Aggressive behavior such as stealing toys, pushing other children, and starting fights was measured in both groups. The study showed that children who attended day care for more than 30 hours per week were about three times more likely to be aggressive than those who stayed home. Although the aggressive behavior observed in the study was well within the normal range for healthy children, these statistics have been used to persuade parents to keep their children at home until they start school.

Abuses

Confounding Variables The U.S. study found that the results were the same regardless of quality of the day care center and income of the family. However, the overall quality of care experienced by most of the children studied could be the problem—a survey of American day care centers that measured aspects such as number and expertise of caregivers found that only 10 percent of American day care centers provided high-quality care.

A similar study of preschoolers and aggressive behavior in Norway, where day care centers are subject to strict standards and the ratio of adult caregivers to children is high, found that the link between day care attendance and aggressive behavior was minimal. Another Norwegian study included an additional variable, differences between siblings, and found no relationship between day care attendance and behavior problems. These additional variables that are often out of the researcher’s control are known as confounding variables.

Study Funding A series of studies was conducted on various methods for reducing the number of cigarettes that smokers smoke. The study compared smokers who were simply told to smoke less and those who tried methods such as nicotine replacement therapy, electronic cigarettes, and using reduced tar, carbon, or nicotine cigarettes. Some methods were shown to be effective in reducing the number of cigarettes smoked.

Some of the studies were funded by the tobacco industry, which could profit from promoting strategies other than quitting as beneficial to smokers’ health. When dealing with statistics, it is always good to know who is paying for a study, and whether the researchers are unbiased.

1. Confounding Variables A pharmaceutical company has applied for approval to market a new arthritis medication. The research involved a test group that was given the medication and another test group that was given a placebo. Describe some possible confounding variables that could influence the results of the study.

Expert Solution & Answer
Check Mark
To determine

To describe: The possible confounding variables that could influence the results of the study.

Answer to Problem 1UA

The possible confounding variables that could influence the results of the study are age and medical report.

Explanation of Solution

Given info:

The study based on the pharmaceutical company has applied for the approval to market a new arthritis medication.

Justification:

Confounding variable:

Confounding variable is a third variable that is associated with explanatory and response variables. In other words, confounding variable influences the response variable.

Here, the possible confounding variables that could influence the results of the study are age and medical report.

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Chapter 8 Solutions

Elementary Statistics: Picturing the World (7th Edition)

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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