Okay, so the number in front of the x^2 term controls the vertical "stretch" of the function.
A number less than one makes the graph fatter or less steep, whilst a number greater than one makes the graph skinnier or more steep.
2x^2 would fall entirely within x^2, whereas 1/2x^2 would fall entirely outside of x^2. You can see this if you complete the tables and plot the points.