Bell Curve Differences Between Groups The variation is tiny, with the only meani

Bell Curve Differences Between Groups
The variation is tiny, with the only meaningful differences being tail effects. There is far more genetic load (defect) in the left tail of african populations, and far more advantage in the right tail of English Anglican, and double that in Ashekanazis. So that for every Anglican outlier there are twice as many Ashkenazi outliers.

–“the Asian advantage is 4 points on verbal and 59 on math. The white standard deviation is about 103, so Asians have an advantage of 4/103=0.04 d and 59/103=0.57 d. The overall advantage is complicated to calculate but will be a little more than the average of these values (0.31), so about 0.35 d, or 5.25 IQ equivalent points.”–

Where 1/2 SD = 7.5 Points. And half an SD is the point of ‘demonstrated marginal difference’.
Now test prep does help and asian test prep is legendary, with 30% of east asians prepping, and only 10% whites. Which reduces the white-asian SAT gap by about 1/3. But the gap still remains.
The reason is group differences in neoteny and cognitive dimorphism, which is a bit deep for this conversation.