William Stern's formula for the intelligence quotient was mental age divided by chronological age and then multiplied by 100.What is the IQ of a 12-year-old with a mental age of nine?
A)125
B)135
C)75
D)85

Question

Quizplus · Accepted Answer

Using Stern's formula: IQ = (mental age / chronological age) x 100 
For this situation, the calculation is: IQ = (9/12) x 100 = 75

William Stern's Formula for the Intelligence Quotient Was Mental Age