Mental Age and IQ
Originally, the differences between mental age and chronological age were used to compute the intelligence quotient, or IQ. This was computed using the ratio method, with the following formula: mental age/chronological age * 100 = IQ. No matter what the child's chronological age, if the mental age is the same as the chronological age, then the IQ will equal 100.
An IQ of 100 thus indicates a child of average intellectual development. For a gifted child, the mental age is above the chronological age, and the IQ is higher than 140; for an intellectually challenged child, the mental age is below the chronological age, and the IQ is below 70.
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Famous quotes containing the words mental and/or age:
“The entire construct of the “medical model” of “mental illness”Mwhat is it but an analogy? Between physical medicine and psychiatry: the mind is said to be subject to disease in the same manner as the body. But whereas in physical medicine there are verifiable physiological proofs—in damaged or affected tissue, bacteria, inflammation, cellular irregularity—in mental illness alleged socially unacceptable behavior is taken as a symptom, even as proof, of pathology.”
—Kate Millett (b. 1934)
“Raise children for your old age as you would store up grain against famine.”
—Chinese proverb.