Fig. 5

Software output for the PLS regression model, based on 5 latent variables, for the hardness determination by EBT-CC sensor. The different colours refer to two different experiments at low (red) and high (green) hardness degree. (1) Comparison of the experimental points with the points recalculated from the model; (2) the same comparison but in conditions of cross-validation. This plot assesses the variability of the estimated parameters and its effect on the prediction