In experimental psychology, the proportion of the top third of the class that correctly answered the last question of the final was .93 while .89 of the bottom third of the class answered correctly. The professor should decide not to include this question in the next final because the discrimination index indicates
A)negative discrimination.
B)chance level performance.
C)that students were incorrectly prepared.
D)that the item does not discriminate well.

Question

Quizplus · Accepted Answer

The discrimination index measures how well an item (in this case, a test question) can differentiate between high and low performers. A high discrimination index means the question is good at distinguishing between those who generally perform well and those who do not. In this scenario, because both the top and bottom thirds of the class had high correct response rates (.93 and .89, respectively), the question did not effectively discriminate between higher and lower ability students, indicating it does not discriminate well.

In Experimental Psychology, the Proportion of the Top Third of the Class