Panels A and B present the ratio of the observed versus predicted minute ventilation () for the population (A) and the individual post hoc (B) model fits, as a function of time. Performance metrics for the respective models (i.e., median prediction error [MDPE] and median absolute prediction error [MDAPE]) are also indicated. Panels C and D show the goodness of fit (green dotted line) for the population prediction (C) and the prediction based on the individual post hoc estimates (D) versus the observed minute ventilation, using linear regression (line of identity is depicted in black). The color of lines or dots discriminates between the two different study groups, as indicated in graphs B and D. OSA, obstructive sleep apnea (study group assignment: yes /no).