The Bell curve is a fact of life. The blacks on average score 85 per cent on IQ and it is accurate, nothing to do with culture. The whites score on average 100. Asians score more. The Bell curve authors put it at least 10 points higher. These are realities that, if you do not accept, will lead to frustration because you will be spending money on wrong assumptions and the results cannot follow.
"Lee Kuan Yew: The Man and His Ideas". Book by Fook Kwang Han, Sumiko Tan, and Warren Fernandez, 1998.