Distribution of logarithm of fluctuation parameter (ϵ) as a function of log pulsation period shown in the upper panel. Scatter points represent LMC F (red), LMC 1O (green), SMC F (purple), and SMC 1O (gray) samples, with linear fits to each sample displayed in the corresponding colour. The lower panel includes the same sample, along with Galactic F-mode Cepheids from Csörnyei et al. (2022) (blue plus symbols). Broken linear regressions are shown for the Galactic, LMC, and SMC F-mode samples, respectively.