Earlier quoted context omitted.
That tells you more about the inadequacy and bias of the IQ system in measuring and representing intelligence, than it tells you about African people.
I might be feeding a troll here(2 day old account - http://news.ycombinator.com/user?id=opticksversi ) but IQ is more a measure of a nations current economic development than something inherent in the population. See the Flynn Effect - http://en.wikipedia.org/wiki/Flynn_effect
If that were the case, what would explain the outliers -- high-IQ nations that are poor, and low-IQ nations that are rich?