The formula D = U − L is used to calculate which one of the following statistics?
A) discrimination index
B) difficulty level
C) item-total correlation
D) item-total index

Question

The formula D = U − L is used to calculate which one of the following statistics? 
A) discrimination index
B) difficulty level
C) item-total correlation
D) item-total index

Quizplus · Accepted Answer

The formula D = U - L is used to calculate the discrimination index, which measures how well an item discriminates between high and low performers on a test. U represents the proportion of upper group scorers who answer the item correctly, and L represents the proportion of lower group scorers who answer the item correctly. Subtracting L from U gives the discrimination index, which can range from -1 to 1.

The Formula D = U − L Is Used to Calculate