The optimum item difficulty index for a multiple-choice item
A) is unaffected by the number of options.
B) varies directly with the number of options.
C) varies inversely with the number of options.
D) ranges from .30 to .70 for true-false tests.

Question

Quizplus · Accepted Answer

The optimum item difficulty index varies inversely with the number of options because as the number of options increases, the probability of guessing the correct answer decreases, thus requiring a lower difficulty index for optimal discrimination.

The Optimum Item Difficulty Index for a Multiple-Choice Item