Left: comparison of the time-scales τ_M (red) and E[τ] (magenta). The lines are calculated for α from the set {0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8}, avoiding set C_M. Middle: as in the left panel, but for α = 0.9. For low K this corresponds to double-peaked power spectra. The red curves correspond to 1 over the peak frequency, the green is for the minimum. The blue curve denotes the time-scale 1 / E[1 / τ]. Right: comparison of the time-scales τ_M (red) and 1 / E[1 / τ] (blue).