Panels A, B, C, and D show the relation between effective yield and stellar mass, total baryonic mass (stellar+neutral atomic mass), metallicity gradient and residual metallicity gradient (after removing the stellar mass dependence). In each panel the green dashed horizontal line represents the true stellar oxygen yield derived by Pilyugin et al. (2007), and the red dashed line and the shaded region are the best-fit linear relation and its 1σ uncertainties. The Spearman’s rank correlation coefficient r, p-value and the best-fit slope are given in the upper left corner of each panel. In panel B we also plot the best-fit relation from Tremonti et al. (2004).