Table 1.

Result of principal component analysis

	Eigen values	Difference	Proportion
(a) Components
Component 1	2.7405	2.5371	0.9135
Component 2	0.2033	0.1472	0.0678
Component 3	0.0561		0.0187
(b) Eigen-vectors
TAR	0.5909	− 0.2093	− 0.7791
TEX	0.5627	0.7990	0.2121
TRP	0.5781	− 0.5637	0.5900
(c) Correlation
Variables	TAR	TEX	TRP
TAR	1
TEX	0.8680	1
TRP	0.9344	0.8069	1