Distribution of the p-value for a constant model as applied to optimal bin and 500 s bin light curves for each source. The threshold lines at p-value = 10⁻⁶ divide the plot into four regions that are colour-coded as in Fig. 5. Yellow points (2789) in the top left corner correspond to sources whose optimal bin light curves are compatible with a constant, while 500 s light curves are not. Red points (787 023) in the top right corner correspond to sources whose light curves are compatible with a constant in both cases. Magenta points (2324) in the lower left corner correspond to sources whose light curves are not compatible with a constant in either case. Blue points (2257) in the lower right corner correspond to sources whose 500 s bin light curves are compatible with a constant, while optimal light curves are not. See also Fig. 5.