Histograms of the periods (top panel) and amplitudes (bottom panel) of group 2 stars. Solid lines give the histograms for the periods and amplitudes of the dominant detected frequency, while dotted lines show the histograms considering all frequencies of the multiperiodic group 2 variables. The bulk of stars with periods between 0.1 and 0.7 d are shown in dark green, while the few stars with periods between 0.7 and 1.1 d are displayed in cyan, in agreement with the color codes adopted in Fig. 10.