Each blue/red dot at (p,ap) records the average of ap(E) over elliptic curves E/Q of root number w(E)=+1/-1 with |Δ(E)| in a varying dyadic interval.
Each purple dot at (p,ap) records the average of w(E)ap(E) over elliptic curves E/Q with |Δ(E)| in a varying dyadic interval.
Each purple dot at (p,ap) records the average of w(E)ap(E) over elliptic curves E/Q with |Δ(E)| in a varying dyadic interval. The green line shows a least squares fit using a piecewise polynomial function.