Left panel: the r_eff/ε statistical distribution as a function of ε for the random field case. The blue solid circles represent the median, and the gray shaded area represents the 1-σ confidence level region, for each value of ε. Right panel: the same as in the bottom left panel for the sky test field 1. The red solid circles represent the median of the true clusters case, and the grey area the 1-σ confidence level region. The dashed line shows the 1-σ confidence level region, for the fake clusters.