Fig. 2From: Predicting medical usage rate at mass gathering events in Belgium: development and validation of a nonlinear multivariable regression modelCalibration of the PPR regression tree adjusted for Tmax. a Calibration for the dataset used for model development on a linear scale; b the same data plotted on a logarithmic scale. The solid red line represents a perfect match between the observed and predicted PPR; the dotted red lines indicate 25% under- or overestimationBack to article page