I'll freely admit that my knowledge of (or lack thereof) American culture has been completely shaped by artists such as Ice Cube, Tupac and the Notorious BIG amongst many others, as well as film and television such as 8 Mile, Coming to America, White Men Can't Jump, He Got Game and The Fresh Prince of Bel Air.
Unambitiousus.com (2013)
However, representations through film, television and music very rarely stay true to real life. This is because film and television often rely on assumptions and stereotypes to make characters recognisable and relateable. Benshoff and Griffin explain these stereotypes as 'oversimplified and overgeneralised assumptions' which 'inevitably create erroneous perceptions about individuals' (Benshoff and Griffin, 2009, pp.42-43). These representations and stereotypes of gangsters, rappers and streetballers are fact to me, partly because I don't know any better having no actual experience to base my opinions on, and partly because these stereotypes are enforced to such a degree that they have almost become impenetrable parts of popular culture.
http://www.defjam.com/artists/beastie-boys/
The rapper for example is almost always an African American male, laden with chains 'bling' and baggy clothing, and often associated with gangs. This stereotype is occasionally challenged by white artists such as Eminem or the Beastie Boys, however the stereotype still endures because it is still embedded in the psyche, and to an extent perpetuates itself when people recognize it and act accordingly.
References
Benshoff, H, Griffin S 2009, America on Film: Representing Race, Class, Gender, and Sexuality at the Movies, Blackwell Publishing, United Kingdom, pp.42-43.