Evolution of mass-weighted metallicity PDFs of quiescent population along cosmic time for different stellar mass bins. Panels a–c: illustrate the evolution of the medians of mass-weighted metallicity PDFs, whereas panels g–i show the widths of the mass-weighted metallicity PDFs. From left to right, results obtained using the SSP models of BC03 (panels a and d), EMILES with BaSTI isochrones (panels b and e), and EMILES with the Padova00 ones (panels c and f). The shaded regions enclose the 1σ uncertainties of both parameters. The grey region limits the age of the Universe at any redshift. The square-shaped markers illustrate the average median and width assuming for the MLE deconvolution μ₂ = μ₁ = σ₂ = σ₁ = 0.