Question

The formula of IQ is:

• A. (Mental Age/Chronological Age) × 100
• B. (Chronological Age/Mental Age) × 100
• C. 2(Mental Age/Chronological Age) × 100
• D. 2(Chronological Age/Mental Age)× 100

Hint:

To remember the formula, think logically: if you are "smarter" than your age, your Mental Age should be {higher} than your Chronological Age, resulting in an IQ {above} 100. This only works if Mental Age is in the numerator (on top).

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
The question asks for the original formula used to calculate the Intelligence Quotient (IQ), often referred to as the ratio IQ.
Step 2: Key Formula or Approach:
The concept of IQ was proposed by the German psychologist William Stern and adopted by Lewis Terman for the Stanford-Binet Intelligence Scale. The formula is designed to represent a person's intelligence level as a ratio of their mental development to their actual age. The formula is:
\[ \text{IQ} = \frac{\text{Mental Age (MA)}}{\text{Chronological Age (CA)}} \times 100 \] The multiplication by 100 is to eliminate the decimal and present the IQ as a whole number, with 100 being average.
Step 3: Detailed Explanation:
(A) (Mental Age/Chronological Age) × 100: This correctly represents the formula. If a 10-year-old child (CA=10) has the mental abilities of an average 12-year-old (MA=12), their IQ would be (12/10) * 100 = 120.
(B) (Chronological Age/Mental Age) × 100: This inverts the correct ratio.
(C) and (D) are incorrect as they introduce an arbitrary factor of 2.
Step 4: Final Answer:
The correct formula for IQ is (Mental Age/Chronological Age) × 100.