Bundle: Introduction to Statistics and Data Analysis, 5th + WebAssign Printed Access Card: Peck/Olsen/Devore. 5th Edition, Single-Term
5th Edition
ISBN: 9781305620711
Author: Roxy Peck, Chris Olsen, Jay L. Devore
Publisher: Cengage Learning
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Textbook Question
Chapter 2.3, Problem 38E
The Institute of Psychiatry at Kings College London found that dealing with infomania (information overload) has a temporary, but significant derogatory effect on IQ (Discover, November 2005). Researchers divided volunteers into two groups. Each subject took an IQ test. One group had to check e-mail and respond to instant messages while taking the test, and the second group took the test without any distraction. The distracted group had an average score that was 10 points lower than the average for the control group.
Explain why it is important that the researchers created the two experimental groups in this study by using random assignment.
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The Institute of Psychiatry at Kings College London found that dealing with infomania (information overload) has a temporary, but significant derogatory effect on IQ.† Researchers divided volunteers into two groups. Each
subject took an IQ test. One group had to check e-mail and respond to instant messages while taking the test, and the second group took the test without any distraction. The distracted group had an average score that was
10 points lower than the average for the control group.
Explain why it is important that the researchers created the two experimental groups in this study by using random assignment.
O Without random assignment, the researchers cannot make multiple observations for each group.
O Without random assignment, the researchers can't hold extraneous variables constant.
O Using random assigment ensures the conclusion can be generalized to a larger population.
O Using random assignment produces comparable, unbiased experimental groups.
O Using random assigment…
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…
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…
Chapter 2 Solutions
Bundle: Introduction to Statistics and Data Analysis, 5th + WebAssign Printed Access Card: Peck/Olsen/Devore. 5th Edition, Single-Term
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