An Introduction to Statistical Methods and Data Analysis
7th Edition
ISBN: 9780357670620
Author: R. Lyman Ott; Micheal T. Longnecker
Publisher: Cengage Learning US
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Chapter 2.8, Problem 2E
In the following descriptions of a study, confounding is present. Describe the explanatory and confounding variable in the study and how the confounding may invalidate the conclusions of the study. Furthermore, suggest how you would change the study to eliminate the effect of the confounding variable.
- a. A hospital introduces a new screening procedure to identify patients suffering from a stroke so that a new blood clot medication can be given to the patient during the crucial period of 12 hours after stroke begins. The procedure appears to be very successful because in the first year of its implementation there is a higher rate of total recovery by the patients in comparison to the rate in the previous year for patients admitted to the hospital.
- b. A high school mathematics teacher is convinced that a new software program will improve math scores for students taking the SAT. As a method of evaluating her theory, she offers the students an opportunity to use the software on the school’s computers during a 1-hour period after school. The teacher concludes the software is effective because the students using the software had significantly higher scores on the SAT than did the students who did not use the software.
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A retail chain is interested in determining whether a digital video point-of-purchase (POP) display would stimulate higher sales for a brand advertised compared to the standard cardboard point-of-purchase display. To test this, a one-shot static group design experiment was conducted over a four-week period in 100 different stores. Fifty stores were randomly assigned to the control treatment (standard display) and the other 50 stores were randomly assigned to the experimental treatment (digital display). Compare the sales of the control group (standard POP) to the experimental group (digital POP).
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Chapter 2 Solutions
An Introduction to Statistical Methods and Data Analysis
Ch. 2.8 - In the following descriptions of a study,...Ch. 2.8 - In the following descriptions of a study,...Ch. 2.8 - A news report states that minority children who...Ch. 2.8 - A study was conducted to determine if the...Ch. 2.8 - Prob. 5ECh. 2.8 - A large auto parts supplier with distribution...Ch. 2.8 - The circuit judges in a rural county are...Ch. 2.8 - Prob. 8ECh. 2.8 - Time magazine, in an article in the late 1950s,...Ch. 2.8 - The New York City school district is planning a...
Ch. 2.8 - A professional society, with a membership of...Ch. 2.8 - For each of the following situations, decide what...Ch. 2.8 - For each of the following situations, decide what...Ch. 2.8 - The process engineer designed a study to evaluate...Ch. 2.8 - Prob. 15ECh. 2.8 - In the descriptions of experiments given in...Ch. 2.8 - In the descriptions of experiments given in...Ch. 2.8 - In the descriptions of experiments given in...Ch. 2.8 - A research specialist for a large seafood company...Ch. 2.8 - In Exercises 2.20–2.22, identify whether the...Ch. 2.8 - In Exercises 2.202.22, identify whether the design...Ch. 2.8 - In Exercises 2.20–2.22, identify whether the...Ch. 2.8 - A bakery wants to evaluate new recipes for carrot...Ch. 2.8 - Prob. 24SECh. 2.8 - Prob. 25SECh. 2.8 - Prob. 26SECh. 2.8 - Prob. 27SECh. 2.8 - Prob. 28SECh. 2.8 - Prob. 29SECh. 2.8 - A forester wants to estimate the total number of...Ch. 2.8 - A transportation researcher is funded to estimate...Ch. 2.8 - The department of agriculture in a midwestern...Ch. 2.8 - Prob. 33SECh. 2.8 - A Yankelovich, Skelly, and White poll taken in the...
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