Left: Function Δ²(k, z ≃ 3.6) for our optimistic and pessimistic cases (solid lines) and its statistical uncertainty (shaded regions) estimated for a 16 sq. deg. survey with R = 100. The dotted line shows the white-noise spectrum for EoR-Spec, and the dashed and dot-dashed lines refer to the clustering and shot-noise components, respectively. Right: Cumulative S/N for the spectra shown in the left panel. In both panels, the markers indicate the centre of our k-bins.