Figure 3: THCA comparison: NIR prediction (Y) vs HPLC measurement (X). The solid line indicates a perfect match.  Data shown are for High Times Cup samples not included in the calibration.  Note the red datum, representing a spectrum that mathematically lies outside the calibration set.  Samples lying outside the calibration set are rejected as outliers, since quantitation for these can be unreliable.  Outliers can be detected and removed using objective statistical data analysis procedures.