① In order to accurately express an intelligence level, intelligence measurement experts put forward the concept of deviation IQ, that is, to measure a person's position in his age by calculating how many standard deviations the subjects deviate from the average, which is also called IQ.
② For example, for two adults of different ages, one person's intelligence measurement score is higher than the average score of the same age group, and the other's test score is lower than the average score of the same age group, then we come to the conclusion that the IQ of the former is higher than that of the latter.
③ At present, most of the intelligence measurements use the deviation IQ to express a person's intelligence level.
④ intelligence quotient distribution of population.
in a typical modern intelligence test, if the average IQ of the main population is set at 1, according to certain statistical principles, the IQ of half the population is between 9 and 11, among which 25% of the people have IQs of 9-1 and 1-11 respectively. 14.5% have an IQ of 11-12, 7% have an IQ of 12-13, 3% have an IQ of 13-14, the remaining .5% have an IQ above 14, and 25% have an IQ below 1.
⑤ Extraordinary intelligence and mental retardation
After the advent of intelligence tests, it became easier to distinguish the differences in intelligence. It is found that people with extremely high IQ (IQ above 13) and extremely low IQ (IQ below 7) are in the minority, and those with average or near average intelligence (IQ between 8 and 12) account for about 8% of the total population. Those with intelligence above normal are called abnormal intelligence, and those with intelligence below normal are called abnormal intelligence.