Distribution of central SFR indicators for galaxies with strong arms and the control sample with weak arms. Panels a–d: show the result of sSFR_fiber, C(sSFR), D_n(4000), and Hδ_A, respectively. The distributions for strong-armed galaxies are marked in blue, and the same for the control weak-armed sample are marked in gray. The mean difference between the two distributions and p values from the Kolmogorov–Smirnov test are presented at the top of each panel.