Table 4.

Comparison results of different regression methods of lobetyolin

Regression method	R C	RMSEC (μg/ml)	R CV	RMSECV (μg/ml)	R P	RMSEP (μg/ml)
SMLR	0.8246	8.12	0.7999	8.62	0.7231	11.10
PCR	0.9734	3.29	0.9379	5.00	0.9434	5.76
PLSR	0.9964	1.21	0.9743	3.23	0.9587	5.18

R: correlation coefficient; RMSE: root mean squares error; C: calibration; CV: cross-validation; P: prediction; SMLR: step-wise multiple linear regression; PCR: principal component regression; PLSR: partial least squares regression