Solid red curve: reference mean biasing function of Fig. 3 computed using the mass PDF from N-body simulations. Brown dot-dashed curve and orange band: biasing function obtained using a lognormal fit to the mass PDF and 2σ scatter from the mocks. Blue dashed curve and blue band: biasing function obtained using a skewed lognormal fit to the mass PDF and 2σ scatter from the mocks. Bottom panels: difference Δ_p between the reconstructed and reference PDFs in units of the random error σ_p. Dashed lines indicate systematic errors equals to 1σ_p random errors.