The EW of Fe Kα line versus directly measured N_H for our sample. The lines drawn show the theoretical relationship between the EW of the Fe Kα line and the N_H, calculated from the Monte Carlo simulations, described in Section 2 for a power law with Γ = 2 and solar abundances. The solid blue line shows the calculations for the spherical distribution, the dashed green line shows the calculations from the torus distribution for the equatorial line of sight, and a torus opening angle of θ_tor = 60°. The dotted yellow lines show maximum and minimum EWs observed from unobscured sightlines in the torus distribution, taken from Fig 3, where the line of sight N_H through the torus is greater than 10²³ cm⁻². Thus, all truly unobscured sources must have an EW less than the maximum shown. Sources which are reflection dominated (R > 8) are shown in green. Sources with 1 < R < 8 are shown in blue for comparison. All grey lines are error bars. These are only shown where the EW is consistent with being non-zero (plotted as filled diamonds, otherwise plotted as open diamonds). Arrows indicate upper limits on the N_H.