Pr(X ≤ μ + 1σ) is closer to 84% but sure I was rounding up... It is most explanatory at the low end; Cognitively Challenged. Elsewhere it has a correlation it

Pr(X ≤ μ + 1σ) is closer to 84% but sure I was rounding up... It is most explanatory at the low end; Cognitively Challenged. Elsewhere it has a correlation it is just not as significant, which is not in conflict with your link. If you tested all the Children in the US you aren't going to be able to accurately rule out 84% of them from professional careers by IQ.