explain one way in which sociocultural biases in testing might pose problems for assessing mental retardation.

I searched Google under the key words "sociocultural bias testing mental retardation" to get this:

http://www.google.com/search?client=safari&rls=en&q=sociocultural+bias+testing+mental+retardation&ie=UTF-8&oe=UTF-8

In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search. Also see http://hanlib.sou.edu/searchtools/.