WISE colors vs. [O IV]25.89 μm/W2 luminosity ratio (left panels) and [O III] 5007 Å/Hβ EW ratio (right panels). The red dots are for the PG quasar sample, with the open circles indicating the cases where galaxy emission contributes over 50% of the IR output (from Lyu et al. 2017), the blue crosses are for the SDSS-Spitzer sample (left panels) and background gray contours are the distribution of the SDSS quasar sample (right panels). The typical 1σ uncertainties of these measurements are ≲5%–10%. The green dashed and blue solid lines are, respectively, the template colors of warm-dust-deficient and normal AGN templates at the average redshift of the sample. The Spearman’s rank correlation coefficients ρ of each sample are denoted in the corresponding color.