Difference in the measured standard correlation function ξ(r) between GR and MG in real space. In the upper panel, the correlation functions themselves are plotted where different colours indicate the underlying gravity theory. The curves show the average over five realisations and the errorbars correspond to the mean standard deviation over these realisations. The lower panel quantifies possible differences in terms of the S/N, as introduced in Sect. 4. Black dashed lines indicate a S/N of ±3. The shaded region refers to the error of a single measurement divided by the mean error of the difference as described in Eq. (38).