[Mz]

IQ tests are somewhat ridiculous to begin with. The first tests that eventually became IQ tests were not intended to measure intelligence. They were intended to measure school readiness of rural children whose birthdates were often not known with certainty. The lack of clear birthdates meant an age cut off could not be used and rural children faced cultural differences from kids in the big city (namely: Paris) that created inherent challenges to them fitting in and doing well in school.

Intelligence is neither well defined nor well understood. It is fairly controversial stuff.