Fractional variability F_var (red) as a function of (N − d) /N for the jackknife-d samples of selected representative light curves. The measured F_var of the original light curve and its error are shown as red horizontal lines. The F_var of the jackknife-samples is constant and agrees with the original F_var within its errors for all but the largest d (i.e., the smallest jackknife-samples).