25 IQ Point difference between upper-class to low-low class
A Normative Sample of Intelligence and Achievement of Negro Elementary School Children in the Southeastern United States Wallace A. Kennedy, Vernon van de Riet and James C. White, Jr.
Lawrence Mishel, Jared Bernstein, and Heather Boushey, The State of Working America 2002–03 (Outside Source). Washington, D.C.: Economic Policy Institute, 2002.
"...in order for children to succeed, they need a social and emotional connection to a role model and in turn the role model needs to give the children an indication that they are loved" (National Center for Educational Statistics [NCES], 2004, p. v)