Dose Correlation of Panax ginseng and Atractylodes macrocephala Koidz. Drug Pairs in the Chinese Medicine Prescription Based on the Copula Function

Table 6

The copula function parameter estimation.

Copula function	Squared Euclidean distance	Parameter estimation	Kendall correlation coefficient	Spearman correlation coefficient
Clayton copula function	0.0247	α = 6.5391	0.7958	0.9207
Frank copula function	0.0214	α = 16.8550	0.6989	0.9426
Gumbel copula function	0.0276	α = 4.3915	0.8211	0.9264
Gaussian copula function	0.0472	ρ = 0.8902	0.7723	0.8810
t-copula function	0.0108	ρ = 0.9608,  = 4.0089	0.7858	0.9276