Diagnostic diagrams with EW of UV emission lines for the different stack sets, color-coded by the parameter used for stacking. The black dashed lines separate AGNs and star-forming galaxies as proposed in Nakajima et al. (2018a). The dotted and dotted-dashed lines are from Hirschmann et al. (2019), meant to separate between SFGs and composite as well as composite and AGN, respectively. Top row: diagnostic of EW(CIII])–CIII]/HeII ratio. The gray shaded region is where the models overlap. Middle row: diagnosis of EW(CIV)–CIV/HeII ratio. Bottom row: diagnosis of EW(OIII])–OIII]/HeII ratio. The green boxes are the composites from Le Fèvre et al. (2019) and the higher the size, the higher the EW (CIII]). The red X mark is the composite from Amorín et al. (2017). The red rectangles are the stacks from Nakajima et al. (2018b) with the brightest M_UV (smallest rectangle), smaller EW(Lyα), faintest M_UV, and larger EW(Lyα) (largest rectangle).