Example showing effect of the Poisson statistics on retrieved spectral parameters (kT₁ vs. kT₃) of the synthetic spectra of the grid with ARs 40%, COs 6–60% and FLs 0–2%. Black circles: medians of the 1000 representations of each grid point; blue triangles: 1000 best-fit parameters representing one specific combination of magnetic structures (ARs 40%, COs 42%, FLs 0.4%); red cross: median of the 1000 representations (plotted in blue) of the model with COs 42% and FLs 0.4%, which we chose to highlight as an example.