If you are trying to graph on your TI83/84 and you get the INVALID DIM error, then this usually means your PLOT is turned on. Follow the steps below to turn off your PLOT and see if the problem is fixed.
Here is what your screen looks like with the error:
From THIS screen, follow these key strokes exactly to turn off your PLOT:
Your Y= area should now look like this:
Whereas before, it looked like this:
A good rule of thumb is, anytime you are using the STATPLOT, be sure to turn OFF your PLOT when you are finished. That way you will avoid the INVALID DIM Error in the future.
Related Post: Turn PLOT on