Monday 3 March 2014

Funny looking kids and the normal distribution


Much shorter version:

Say, through the mischance of illness, birth injury or genetic disorder, 1% of all children are born with something which damages body and mind, such that they look odd in some way, and fall below IQ 70.

Say, through the normal variation of genetic inheritance some children with normal undamaged bodies and minds also fall below IQ 70.

Then in the case of white kids the proportions will be 1% funny looking and 2% normally backward, so 1 in 3 looking odd.

In the case of black kids the proportions will be 1% funny looking and 16% normally backward, so 1 in 16 looking odd.

Black kids below IQ 70 will usually be normal looking, white kids less frequently so.


  1. Jesus! No presence of political correctness there!

    1. Pretence (damn spell checker)

  2. That's at the heart of the 2002 U.S. Supreme Court decision on IQ and the death penalty:

    Just about anybody related to a Supreme Court justice with an IQ below 70 is a funny looking kid.

  3. 2002, and all the arguments and the cast of researchers all the same. Good article.