In a new
La Griffe du Lion, the question whether the properly defined IQ follows a normal, Gaussian distribution is investigated. Also, they ask whether the Gaussian character of their definition of intelligence follows from the central limit theorem or something else.
Prodigy then introduces the diversity space whose two coordinates are "white fraction above threshold" and "black fraction above threshold" (similarly for other pairs of group A,B) and shows a remarkable agreement of his or her Gaussian calculation with observation.
They also claim that the black-white IQ difference is around 16 points while the men-women IQ difference is about 2.4 points. The distribution for women is narrower by a factor of 0.9; blacks seem to have as narrow a distribution as women. An average woman has a 45% probability to be smarter than an average man which, as you might agree, is not too different from 50 percent. There are other quantities, especially those that depend on the different widths of the Gaussians, where the difference escalates.