Radial selection functions modelled as log-normal distributions in redshift (upper x axis) for the three mock galaxy populations. In the figure, the distributions are represented with respect to comoving distances (lower x axis) using the redshift-distance relation. The continuous lines represent the selection functions for the well-specified Model A, while the dotted lines represent the misspecified Model B, both defined by the values provided in Table 4. The small, percent-order difference between Models A and B renders the dotted curves nearly indistinguishable from the solid ones. The vertical dashed lines indicate the means of the log-normal distributions.