Comparison of bar strength indexes. Galaxies are separated into T bins. Spearman’s rank correlation coefficients (together with the significance) are indicated in all the plots for the total sample (see Table 4 for the different morphological types). Systems with relatively massive (faint) bulges are plotted with filled (empty) circles. In the left and central panels, the dotted and dashed lines display a second-order polynomial fit to the data separately for T< 5 and T ≥ 5, respectively. In the right panel we show the linear fits for different morphological classes.