Note that while the MAE of 0.04 is even lower for 𝑆 2 , the corresponding coefficient of determination only yields 0.22, which will not produce reliable predictions. The reason for this can be understood when comparing the distributions of 𝑓 Osc (𝑆 1 ) and 𝑓 Osc (𝑆 2 ) for the training set (cf.