Similar analysis to in Fig. 6, but for composite spectra combining star-forming and AGN spectra. The dashed red line depicts the logarithm of the AGN’s Hα luminosity ratio to the total Hα luminosity of the composite spectra. Although the transition from star-forming to AGN galaxy occurs when the AGN’s fractional contribution to the nuclear SDSS g-band continuum approaches ∼40%, the corresponding Hα fractional contribution is ∼30.