The dependent variable is the one on the Y (vertical) axis
The independent variable is the one on the X (horizontal) axis
OH OH OH
i just remembered, in 6th or 7th grade, my science teacher gave us a way to remember which is which.
DRY MIX
DRY - Dependent (Responding) is on the Y axis
MIX - Manipulated (Independent) is on the X axis
Hope this helps!