Mean experimental values as a function of predicted responses for random combinations in Table
. Mean experimental values (β) result from 3 independent sets of cultures and measurements. Predicted responses (ŷ) were calculated from Equations 1 to 6 (2nd-round models). The diagonal full straight line represents a perfect match of the model (y = ŷ). In panel a, axis scaling is identical to that of Figure 4 to facilitate visual comparison. The framed zone in panel a is enlarged in panel b, in which scaling is adapted to data points and standard deviations are drawn except in case of they are comprised within the limits of the markers. For P800, standard deviations are presented in panel a since it was not necessary to adapt scaling.