When an item-characteristic curve of an ability test has an inverted U shape,it usually indicates that
A) testtakers of moderate ability have the highest probability of answering the item correctly.
B) testtakers of low ability have the highest probability of answering the item correctly.
C) testtakers of high ability have the highest probability of answering the item correctly.
D) the item is working as well as any item on this test could be expected to work.

Question

Quizplus · Accepted Answer

When an item-characteristic curve of an ability test has an inverted U shape, it means that the item is relatively easy for high-ability test-takers and relatively difficult for low-ability test-takers. However, the item is most suitable for those with moderate ability, who have the highest probability of answering the item correctly. Therefore, the best choice is option A, which states that test-takers of moderate ability have the highest probability of answering the item correctly.

When an Item-Characteristic Curve of an Ability Test Has an Inverted