High school: Nationwide, black students graduated at a rate of 69 percent; Hispanics graduated at 73 percent; whites graduated at a rate of 86 percent.
13.2% of the population is black, 17.1% Latino, 63% white.
If White = (38%) then you would expect black to be: 38% / (.63 * .86) * (13.2 * .69) = 6.39%. So if anything Standford is about right for black people, and massively over represents Asians.
It seems like HS graduation rates are the real issue everything else just flows from that. But, income and graduation rates are linked so it's a self perpetuating cycle.