Mean biasing function of mock VIPERS galaxies computed from counts in cells of R = 4h^-1 Mpc  (bottom panel) and R = 8h^-1 Mpc  (top panel). The magnitude cut and redshift range of the mock VIPERS subsample, indicated in the plot, are the same as Fig. 2. Solid red curve: reference biasing function obtained from the Parent mock catalogues. Blue dashed curve and blue-shaded region: average value and 2σ scatter of the biasing function reconstructed from the Realistic mocks using the Γ_E method. Brown dot-dashed curve and orange-shaded band: average value and 2σ scatter of the biasing function reconstructed from the Realistic mocks using a “direct” estimate of the galaxy PDF. Bottom sub-panels: difference Δ_p between the reconstructed and reference PDFs in units of the random error σ_p. Dashed lines indicate systematic errors equal to 1σ_p random errors.