The distributions of two kinds of waiting times between precursors and main bursts (upper panel: differential and cumulative size distributions, lower panel: size difference distributions). Panels (a2) and (b2) show the size difference distributions of peak-time intervals (Δt _p1) and quiescent times (Δt _p2) for n = 1 (red), n = 5 (green), n = 10 (blue), n = 15 (orange), and n = 20 (purple), respectively. The shadow regions represent the 95% confidence level, the smooth lines are the best fits. Panel (e) shows the best-fit values of q in the q-Gaussian distributions as a function of n for peak-time intervals (the filled symbols) and quiescent times (the open symbols).