Histograms showing the maximum detection level for void temperatures (upper left panel; 0.2% of the simulations have a higher maximum detection level), the mean detection level for void temperatures (upper right panel; 0.2% of the simulations have a higher mean detection level), the maximum detection level for void temperatures using only voids with Δ_LOS < 0 (lower left panel; 0.03% of the simulations have a higher maximum detection level), and the mean detection level for void temperatures using only voids with Δ_LOS < 0 (lower right panel; 0.09% of the simulations have a higher mean detection level). All cases are based on 9000 simulations and the free parameters (void size, wavelet scale, and the ratio of the void radius) are either varied to optimize the detection for each simulation (for maximum detection) or the significances are averaged over the parameter values in Table 1 (mean detection). The vertical lines show the same number for the real data.