Re: Why g differs from experimental g, even when adjusting for Inertia?

33 percent does seem large. Are you sure that you took into consideration 
the inertia (rotational inertia of the pulley? YOu say that you took into 
consideration the inertia and pulley mass, but you do not say how you did 
this.  For instance, if the pulley is a disk, then the inertia is 1/2 mr^2 
This could be where the problem lies.

PS, what did you graph?  what were the vertical and horizontal axes?