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 ?