Shelly took the Stanford-Binet test at age 10 and scored a mental age of 13. Using Stern's formula, her IQ is

• A. 13
• B. 30
• C. 100
• D. 130

Answer: (D)

Verified step by step guidance

1. Understand that the Stanford-Binet test measures intelligence by comparing mental age to chronological age.
2. Recall Stern's formula for calculating IQ: \( IQ = \frac{\text{Mental Age}}{\text{Chronological Age}} \times 100 \).
3. Identify Shelly's mental age as 13 and her chronological age as 10.
4. Substitute the values into Stern's formula: \( IQ = \frac{13}{10} \times 100 \).
5. Perform the multiplication to find the IQ score, but remember not to calculate the final result as per the instructions.