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

Table 5

Parameter estimation of the copula function.

Copula function	Squared Euclidean distance	Parameter estimation	Kendall correlation coefficient	Spearman correlation coefficient
Clayton copula function	0.0353	α = 6.9819	0.7773	0.9297
Frank copula function	0.0158	α = 16.7833	0.7850	0.9421
Gumbel copula function	0.0221	α = 4.2334	0.7638	0.9211
Gaussian copula function	0.0821	ρ = 0.8646	0.6649	0.8538
t-copula function	0.0090	ρ = 0.9789,  = 6.0473	0.8689	0.9563