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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Textbook Question
Chapter 2.4, Problem 51E
Swedish researchers concluded that viewing and discussing art soothes the soul and helps relieve medical conditions such as high blood pressure and constipation (AFP International News Agency, October 14, 2005). This conclusion was based on a study in which 20 elderly women gathered once a week to discuss different works of art. The study also included a control group of 20 elderly women who met once a week to discuss their hobbies and interests. At the end of 4 months, the art discussion group was found to have a more positive attitude, to have lower blood pressure, and to use fewer laxatives than the control group.
- a. Why would it be important to determine if the researchers randomly assigned the women participating in the study to one of the two groups?
- b. Explain why you think that the researchers included a control group in this study.
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Studies have suggested that alcohol abuse and disorders are found to be more prevalent during early adulthood than in any other age group, with about 9% of young adults (age 18 to 29 years) meeting the criteria to be labeled as alcoholic. In addition, surveys have shown that college students tend to drink more than their peers who do not attend college.
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n1 = 255
n2 = 150
y1 = 96
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p̂1 =
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150
(a)
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(b)
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sample of 82 U.S. workers…
Suppose you are conducting a study about how the average U.S. worker spends time over the course of a workday. You are interested in how much time workers spend per day on personal calls, e-mails, and social networking websites, as well as how much time they spend socializing with coworkers versus actually working.
The most recent census provides data for the entire population of U.S. workers on variables such as travel time to work, time spent at work, and break time at work. The census, however, does not include data on the variables you are interested in, so you obtain a random sample of 82 full-time workers in the United States and ask about personal calls, e-mails, and so forth. You are curious about how your sample compares with the census, so you also ask the workers the same questions about work that are asked in the census.
Suppose the mean break time per day from the most recent census is 29.6 minutes, with a standard deviation of 16.0 minutes. Your sample of 82 U.S. workers…
Chapter 2 Solutions
Introduction to Statistics and Data Analysis
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