Performance of the regression models when 300 MZSs were considered during the training process. The X axis for all panels corresponds to the original value of H_eff for each of the 1500 MZSs. In the upper panels the Y axis represents the predicted values of the inversions, while in the lower panel it corresponds to the inversion errors in units of Gauss. The red line in the upper panels represents a one-to-one relation.