λ (nm) RMSEP R2test Q2test AM           238 0.281 0.960 0.953   268 0.506 0.914 0.849   269 0.498 0.917 0.854   270 0.524 0.909 0.838 AT           235 1.107 0.968 0.966   256 0.968 0.975 0.974   309 1.075 0.972 0.968   310 1.027 0.974 0.971

Table 5: Statistical performances of CWT zero-crossing in external test set prediction.