Plot of the dependent variable (DV) i.e. observed TYL serum concentrations (µg/mL) versus individual predicted (IPRED) serum concentrations in arithmetic (top) and logarithmic (bottom) scale. The IPRED plots were obtained by setting random effects to the “post hoc” or empirical Bayesian estimate of the random effects for the individual from which the dependent variable (DV) observation was made. Thus, the plots show observed vs fitted values of the model function. Ideally, points should fall close to the line of unity y = x.