To study the effectiveness of a new anti-anxiety drug, researchers randomly assign equally anxious people to two groups, one getting Drug X and the other getting no drug. The researchers mistakenly conclude that Drug X works because people in the drug group show fewer signs of anxiety than the others. What is the mistake?
a. They never introduced an independent variable.
b. They did not create a placebo control group.
c. They never did a pretest of anxiety symptoms.
d. They did not operationally define what the experimental group was.
B
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Before the accident, Clive enjoyed singing and playing the piano. Because of the brain damage, he cannot learn new songs. Why would he remember old songs, but fail to learn new ones?
A. Since his cortex is damaged, information like songs cannot be transferred into short-term memory. B. The words of the songs learned before the accident were already safely stored throughout his cortex. C. Brain damage often reduces one's motivation for new learning. D. The accident probably damaged his brainstem, thus preventing new songs from being stored in his hippocampus.
The measure of central tendency that is most sensitive to extreme scores within the data set is:
a. the mode b. the median c. the standard deviation d. the mean
A cohort is a(n)
a. control group b. experimental group c. nonequivalent control group d. group of subjects that has something in common, such as year of birth
In Rogers's nondirective approach to therapy, the focus is on growth initiated by the client
Indicate whether the statement is true or false