Intelligence Quotient, or IQ, is a score used by standardized tests as a means of describing one’s intelligence level. The formula for IQ is (mental age / chronological age) x 100. An average score is 100; about 95% of IQ scores fall between 70 and 130.
Example: After taking an IQ test, a precocious little girl learns that her score is an above-average 120.
Last reviewed: By John M. Grohol, Psy.D. on 20 Oct 2008