I don't think IQ varies much by race, more like you need the IQ and the ability to attend ( pay for) college in order to become a doctor or something.
The poor black kid in Detroit may have the IQ ( born with it) but goes to SHIT schools, and doesn't get nearly as much chance for a scholarship, so then if/when he even graduates HS, he has to go right to work at Walmart, and becoming a doctor doesn't have much hope. He could join military, but that is still a much harder path to college.
The middle class white kid has an easier path, likely goes to much better schools, and possibly can go right to college after HS.
Any source of IQ by race ?
http://en.wikipedia.org/wiki/Race_and_intelligence_(test_data)
IQ test score gap in the US
In the United States, the mean IQ score among Blacks has at times been measured as approximately 85 and the mean IQ score among Whites has at times has been measured as approximately 100;<sup id="_ref-IQconsensus_0" class="reference">[13]</sup> the mean IQ score of Latinos has been reported to be measured as approximately 89 for unspecified dates.<sup id="_ref-12" class="reference">[14]</sup>
The mean score for people of East Asian and Jewish descent is usually higher than the mean score of Whites, but the extent of that difference is not precisely known. However, several studies place the median IQ of Ashkenazi Jews (who make up the overwhelming majority of American Jews<sup class="noprint Template-Fact">[citation needed]</sup>) at approximately one standard deviation above the mean for other Whites, with the primary Jewish advantage in verbal reasoning and the East Asian advantage primarily in spatial reasoning. In The Bell Curve, Herrnstein and Murray report mean IQ scores for East Asians and Jewish Americans of 106 and 113 (on a scale where Whites = 103), respectively.
Similar gaps are seen in other tests of cognitive ability, including university admission exams such as the SAT and GRE as well as employment tests for corporate settings and the military (Roth et al. 2001).