[marginalia_nu]

No, it is not. 68.2% of the population is in the average span of 85-115 IQ. 15.9% is in the below-average span of 0-85.

[goohle]

> No, it is not. 68.2% of the population is in the average span of 85-115 IQ.

Yep, 50% of them are below 100 IQ, 50% are above 100 IQ.

Official definition of IQ: measure average IQ of a population, then label the point where 50% of population is below average as 100 IQ points.

[readflaggedcomm]

It is. Specifically, IQ is assumed or asserted to follow the normal distribution, where mean equals median and mode.

By definition, half are below the median. The normal distribution's median is equal to the mean, so half are below mean.