IQ is a sort of standard score that reflects how far an individual’s mental capacity is above or below that of his or her peer group. The peer group score is 100, which is calculated by administering the same test to a large number of people from various socioeconomic backgrounds and averaging the results.

In 1912, psychologist William Stern invented the word IQ to refer to the German term Intelligenzquotient. IQ Test was then expressed as a ratio of mental age to chronological age multiplied by 100. As a result, if a 10-year-old had a mental age of 10, their IQ would be 100. If, on the other hand, their mental age was older than their chronological age (e.g., 12 rather than 10), They’d have an IQ of 120. Similarly, their IQ would be lower than 100 if their mental age was lower than their chronological age.

The average score of the norming sample was set as IQ 100 when modern IQ tests were established, and standard deviation (a statistical term that reflects average dispersion) was defined as, for example, 16 or 24 IQ points higher or less than 100. Mensa accepts those who score in the top 2% of the population on a variety of exams as long as they’ve been standardised and normed, and they’ve been accepted by professional psychologists’ organisations. ‘Stanford-Binet’ and ‘Cattell’ (described in m) are two of the most well-known IQ tests.