Definitely, but the author is still right to point out that black people are overrepresented in the sample. You could argue that there is still a gap between black and white Americans in terms of education, wealth, etc., and IQ is partially influenced by environmental factors such as maternal/paternal education level (http://www.sciencedirect.com/science/article/pii/S0899900707...).

Here is a good start

https://en.wikipedia.org/wiki/Race_and_intelligence

Did you read your own source?

> Currently, there is no non-circumstantial evidence that these differences in test scores have a genetic component,

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> Soon, other studies appeared, contesting these conclusions and arguing instead that the Army tests had not adequately controlled for the environmental factors such as socio-economic and educational inequality between African-Americans and Whites.

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> The majority of anthropologists today consider race to be a sociopolitical phenomenon rather than a biological one,[34] a view supported by considerable genetics research.

I didn't mean to imply that I knew the answer to your question. I meant that the IQ disparity is a statistical fact, but the cause is a hotly debated area of research without clear answers, and the Wikipedia page is a good primer on the various sides of the debate. The point is that in a study like this you may have to adjust for oversampling by race.