There is still confusion about dependent and independent variables. The following link should be helpful.
http://nces.ed.gov/nceskids/help/user_guide/graph/variables.asp
Also, I found this sentence that should help. If you fill in the blanks and the sentence makes sense, then you have identified the variables correctly:
(Independent variable) causes a change in (Dependent Variable) and it isn't possible that (Dependent Variable) could cause a change in (Independent Variable).
