Generally, people classify the intelligence level as follows: those with IQ above 14 are called geniuses, those with IQ of 12-14 are the best, those with IQ of 1, 11 and 12 are excellent, those with IQ of 9-1 are mediocre, those with IQ of 8-9 are sub-normal, those with IQ of 7-8 are borderline normal, and those with IQ of 6-7 are mildly mentally retarded.

Intelligent Quotient (German: Intelligenzquotient), abbreviated as IQ (German: IQ), is to measure the score of people's cognitive ability ("intelligence") at their age by intelligence test. People's IQ is normally distributed. At present, the main intelligence tests (including Wexler Adult Intelligence Scale, which is most commonly used) all adopt the definition of deviant IQ scores. That is, the IQ score of an individual will be compared with the norm to which the individual belongs (for example, with people of the same age and country). The average IQ score of this norm is 1, and the standard deviation is 15. The calculation formula of IQ is as follows: IQ = Ma÷÷÷÷÷÷é1, and IQ indicates people's intelligence. The higher the IQ, the smarter it means. Physiological age refers to the actual age of a child after birth. Intellectual age or psychological age is the age measured according to intelligence measurement.