MINDTAP PSYCHOLOGY FOR GRAVETTER/FORZAN
5th Edition
ISBN: 9781305264953
Author: Forzano
Publisher: IACCENGAGE
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Chapter 8, Problem 2EA
A recent survey at a major corporation found that employees who regularly participated in the company fitness program tended to have fewer sick days than employees who did not participate. However, because the study was not a true experiment, you cannot conclude that regular exercise causes employees to have fewer sick days.
- Identify another factor (a confounding variable) that might explain why some employees participated in the fitness program, and why those same employees have fewer sick days.
- Describe how the factor you identified in Part a is controlled in your experiment.
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A recent company survey found that employees who were regular participants in the company fitness program had fewer sick days compared to employees who did not participate. However, because this study was not a true experiment, a cause-and-effect relationship between regular exercise and fewer sick days cannot be determined.
Identify a confounding variable that might explain the relationship between regular exercise and fewer sick days that was found by the company survey. Describe a between-subjects design that you could use to determine whether participation in the exercise program caused fewer sick days. What factors would you control for (don’t forget about the confounding variable you previously identified!)? How would a repeated measures (within-subjects) design be different, and would it be appropriate for answering this research question? Why or why not?
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A researcher conducts an independent-measures study examining how the brain chemical serotonin is related to aggression. One sample of rats serves as a control group and receives a placebo that does not affect normal levels of serotonin. A second sample of rats receives a drug that lowers brain levels of serotonin. Then the researcher tests the animals by recording the number of aggressive responses each of the rats display. The data are as follows.
Control Low Serotonin
n = 15 n = 20
M = 18 M = 22
SS = 172.5 SS = 135.0
a. What research design was used to answer this question?
b. What was the scale of measurement for the dependent variable?
c. What was the scale of measurement for the independent variable?
d. Does the drug have a significant effect on aggression? Use an alpha level of .05, two tails.
e. Compute r2 and write an…
Chapter 8 Solutions
MINDTAP PSYCHOLOGY FOR GRAVETTER/FORZAN
Ch. 8.1 - Describe, compare, and contrast the defining...Ch. 8.1 - Explain the general advantages and disadvantages...Ch. 8.2 - Define individual differences and explain how...Ch. 8.3 - Identify the three primary techniques for limiting...Ch. 8.4 - Describe how individual differences influence...Ch. 8.4 - Identify the options for reducing or controlling...Ch. 8.5 - Describe how differential attrition and...Ch. 8.6 - Describe how between-subjects designs are used to...Ch. 8 - In addition to the key words, you should also be...Ch. 8 - Identify the basic features of a between-subjects...
Ch. 8 - In a between-subjects design, each individual...Ch. 8 - Briefly explain how a participant characteristic,...Ch. 8 - Briefly explain how random assignment attempts to...Ch. 8 - Explain the advantages and disadvantages of using...Ch. 8 - Briefly explain why large variance within...Ch. 8 - Explain how holding a participant variable such as...Ch. 8 - Explain how holding a participant variable such as...Ch. 8 - Describe some of the problems that can arise when...Ch. 8 - Describe the advantages of a two-group design...Ch. 8 - A researcher has a sample of 30 rats that are all...Ch. 8 - A recent survey at a major corporation found that...
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- What is an experiment?arrow_forwardWhat is an experiment? Give two examples.arrow_forwardA researcher conducts an independent-measures study examining how the brain chemical serotonin is related to aggression. One sample of rats serves as a control group and receives a placebo that does not affect normal levels of serotonin. A second sample of rats receives a drug that lowers brain levels of serotonin. Then the researcher tests the animals by recording the number of aggressive responses each of the rats display. The data are as follows. Control Low Serotonin n = 10 n = 15 M = 14 M = 19 SS = 180.5 SS = 130.0 A. Does the drug have a significant effect on aggression?Use an alpha level of .05, two tails. H0 = ________________________________________ df = _________________________________________ tcritical =…arrow_forward
- A researcher conducts an independent-measures study to examine how the brain chemical serotonin is related to aggression. One sample of rats serves as a control group and receives a placebo that does not affect normal levels of serotonin. A second sample of rats, low serotonin group, receives a drug that lowers brain levels of serotonin. Then, the researcher tests the animals by recording the number of aggressive responses each of the rats display. See the data below. Is there a significant difference between the control group and the low serotonin group regarding the number of aggressive responses? Control Low Serotonin n = 10 n = 15 M = 14 M = 19 SS = 180.5 SS = 130 Perform a hypothesis test using independent-measures t-test. Use a two-tailed…arrow_forwardA researcher conducts an independent-measures study to examine how the brain chemical serotonin is related to aggression. One sample of rats serves as a control group and receives a placebo that does not affect normal levels of serotonin. A second sample of rats, low serotonin group, receives a drug that lowers brain levels of serotonin. Then, the researcher tests the animals by recording the number of aggressive responses each of the rats display. See the data below. Is there a significant difference between the control group and the low serotonin group regarding the number of aggressive responses? Control Low Serotonin n = 10 n = 15 M = 14 M = 19 SS = 180.5 SS = 130 Perform a hypothesis test using independent-measures t-test. Use a two-tailed…arrow_forwardA researcher conducts an independent-measures study to examine how the brain chemical serotonin is related to aggression. One sample of rats serves as a control group and receives a placebo that does not affect normal levels of serotonin. A second sample of rats, low serotonin group, receives a drug that lowers brain levels of serotonin. Then, the researcher tests the animals by recording the number of aggressive responses each of the rats display. See the data below. Is there a significant difference between the control group and the low serotonin group regarding the number of aggressive responses? Control Low Serotonin n = 10 n = 15 M = 14 M = 19 SS = 180.5 SS = 130 Perform a hypothesis test using independent-measures t-test. Use a two-tailed…arrow_forward
- A large study used records from Canada’s national health care system to compare the effectiveness of two ways to treat prostate disease. The two treatments are traditional surgery and a new method that does not require surgery. The records described many patients whose doctors had chosen one or the other method. The study found that patients treated by the new method were more likely to die within eight years. Explain why this is an observational study and not an experiment.arrow_forwardLike many studies that involve BMI, the above studies are using BMI as a proxy for fat, and fat as a proxy for health. However, there are several problems with this idea. For example, BMI does not take into account bone structure, muscle density, or build. As a result individuals with longer legs have lower BMI because legs weigh less than torsos do, individuals with broader hips or shoulders will have higher BMIS, and body builders usually have an overweight to obese BMI because of muscle concentration. That means that the use of BMI is: a biased indicator that predicts everyone into a higher BMI than they actually are a survival bias problem as it only measures people with muscle density a magnitude misinterpretation issue as BMI is not a very accurate proxy for health a selection bias problem that is only applied to certain demographicsarrow_forwardResearchers investigate how the presence of cell phones influence the quality of human interaction. Subjects are randomly selected from a population and divided into an experimental group that is asked to leave their phones in the front of the room and a control group that are not asked to leave their cell phones at the front of the room. Subjects are left alone for 10 minutes and then asked to take a survey designed to measure quality of interactions they had with others in the experiment. What statistical test is appropriate?arrow_forward
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