Line-of-sight dispersion, σ_kin, versus the mean standard deviation, σ_c, diagram. Fields 1 to 5 are plotted with filled circles and the filled square shows their average. The two dashed lines are from Lagrois et al. (2011) and correspond to the fits applied to M33 H II region samples. The dashed grey lines delineate the spread of the models results around the solid line, which indicates the linear regression applied to the whole sample models (with different angle of inclination). The vertical line indicates the rough separation between the wind-less Champagne flow models (on the left) and the Champagne flow perturbed by the expanding wind-blown bubble models (on the right).