Standardized IQ tests typically use one of three standard deviations: 15, 16, or 24. Standard deviation is a statistical concept that indicates how dispersed the data is. In IQ tests, the average IQ is set to 100, and the standard deviation is set to 15, 16, or 24 to evaluate test results.
The most commonly used standard deviation for IQ tests worldwide is 15, and the IQ MENTOR test, which adopts the Raven's Progressive Matrices test, also uses SD 15. However, MENSA mainly uses a standard deviation of 24, so IQ MENTOR also shows results converted to SD 24.