If 8-year-old Stephanie responds to the original Stanford-Binet with the proficiency of an average 10-year-old child, she would be said to have an IQ of .

125

Explanation: The stanford-Simon Intelligent Quotient scale is used to measure the a child's level of intelligence. It originated from France as a tool to identify student or pupils in need of remedial studies. The Binet-Simon scale was standardized by Lewis Therman using students from the United States and calls the Stanford-Binet scale.

It calculates an individual's intelligence Quotient by dividing the mental age of the child by his or her chronological after and then multiply by 100.

Here,

Stephanie's chronological age is 8,

Mental age is 10

Therefore, (10 ÷ 8) × 100 = 125

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