Comparison of different frequency histograms for all the frequencies that constitute the frequency groups. The light grey histogram shows the frequencies of the filtered data, with a P ≥ 0.10 from the original light curve. Similarly, the dark grey histogram represents the frequencies of the filtered data but with a higher threshold for power spectrum, P ≥ 0.15. The thin grey histogram shows the frequencies of randomised light curves with P ≥ 0.10 in the power spectrum. The thin dark grey histogram is the same as the previous one, but with P ≥ 0.15.