Difference between the measured (O/H)s for R2248 cluster galaxies (filled circles) and the comparison sample of field galaxies (open circles), using the O3N2 metallicity calibration and the expected (O/H)s from the formulations of Lilly et al. (2013) for a primordial infall metallicity Z₀ relative to the yield y, Z₀/y = 0. As a third dimension, the SFRs of the investigated galaxies are shown in units of [M_⊙ yr⁻¹]. The median values for the difference in (O/H) between measurements and predictions for both cluster and field galaxies are plotted as a reference and are represented by the large dark and large open circles respectively. The errors of the median are smaller than the symbols, and therefore cannot be seen in the plot. Only the galaxies from the mass complete bin (9.2 <  log(M/M_⊙) < 10.2) are considered for this investigation. In this bin, the (O/H)s of the cluster galaxies (big filled circle) deviate more strongly from the FMR model predictions (by ∼0.12 dex) than the ones for the field galaxies (big open circle), which are in quite good agreement with the model predictions.