Figure 2. The quality of fit of the pharmacokinetic model to the values for plasma concentration of rapacuronium. The x axis shows time (in minutes) after administration of rapacuronium. The y axis shows the ratio of the measured concentration of rapacuronium to the value predicted by the population pharmacokinetic model (left) or the post hoc fit (right). Each line represents a value from a single person. Healthy volunteers are shown by a solid line (n = 10) and patients with renal failure (n = 9) are shown by a dashed line. If the model fit the data perfectly, all lines would lie horizontally at 1.0. The improved quality of fit of the post hoc values compared with those from the population model is expected in that the post hoc model permits interindividual variability, but the population model does not.