According to Cook and Campbell (1979), if you have evidence that the naturally-occurring groups in a nonequivalent control-group design are NOT equivalent on potential confounding variables,
A) you should find new naturally-occurring groups that are equivalent.
B) you may be able to draw conclusions if you carefully evaluate all potential threats to validity.
C) you should continue with the experiment as planned, because the groups only need to be equivalent on the dependent measure.
D) you may be able to draw conclusions if you reassign participants to different groups.
Question 2
What is a major problem with nonequivalent groups?
A) The groups may differ on the dependent measure(s) at the start of the study.
B) There may be confounding variables not controlled by random assignment.
C) The groups may differ on the independent measure at the start of the study.
D) Both A and B
Campbell biology 8-6 (5of9)
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