Trend of [Mg/Fe] as a function of [Al/Fe] for the MP, M-int1, M-int2, and MR subpopulations (from top to bottom, left to right). The size of each point indicates its probability of belonging to that particular metallicity subpopulation – the larger the symbol, the higher the probability – while gray dots represent the entire sample. The error bar in the top-right corner represents the typical measurement error associated with the data.