Dr. Wickersham wants to examine how light affects participants' performance on a counting task. So she has two groups, one that works under dim light, and one that works under bright lights. She finds that those in the dim-light condition perform better. However, one of her research assistants admits that he gave those in the dim-light condition extra time to complete the task. Now Dr. Wickersham is not sure whether those in the dim-light condition did better because of the lighting or because of the extra time they received. The extra time on the test is an example of a(n):

Question

Quizplus · Accepted Answer

The extra time given to the dim-light condition is not a part of the original experimental design, and therefore can be considered an extraneous variable that affects the results. A is incorrect because the light condition is the independent variable, B is incorrect because the performance on the counting task is the dependent variable, and C is incorrect because a criterion variable is a variable used to determine the success or failure of an outcome, which is not relevant to this scenario.

Dr Wickersham Wants to Examine How Light Affects Participants' Performance