Electric field vs. distance along the axis is shown for a uniformly charged circular ring
Which of the following represents the complete graph?
Both sides of a uniformly charged circular ring is exactly symmetrical
But as you can see the electric field direction on the right is opposite to that on the left of the ring. The graph must be drawn on the 3rd quadrant [Both x and →E negative] However the shape of the graph will be the same. If you think about it the two portions of the graphs are symmetric about the origin.