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

Table 7

The copula function parameter estimation.

Copula function	Squared Euclidean distance	Parameter estimation	Kendall correlation coefficient	Spearman correlation coefficient
Clayton copula function	0.0241	α = 5.8181	0.7442	0.9064
Frank copula function	0.0153	α = 13.3355	0.7370	0.9133
Gumbel copula function	0.0376	α = 3.2661	0.6938	0.8711
Gaussian copula function	0.0400	ρ = 0.8706	0.6726	0.8602
t-copula function	0.0117	ρ = 0.9179,  = 2.6696	0.7403	0.8958