Left: average abundance ratios considering different (sub-)samples and/or different EPIC extraction regions. The O/Fe and Ne/Fe ratios are measured using RGS (cross-dispersion width of 0.8′). For these two ratios there is thus no distinction between the two hot samples or between the two full samples. The error bars incorporate the statistical errors (σ_stat) and the intrinsic scatters (σ_int + 1σ). Right: average abundance ratios estimated from the (0.05 + 0.2)r₅₀₀ sample, measured independently by different combinations of instruments. The error bars incorporate the statistical errors (σ_stat), the intrinsic scatters (σ_int + 1σ), and the uncertainties derived from the different EPIC extraction regions and/or subsamples (σ_region, see left panel).