Table 4.

Model coefficient estimated by regression analyses

Variables	F value	P value
Intercept	–	–
X 1	100.65	<0.0001
X 2	16.85	0.0009
X 3	74.43	<0.0001
X 4	34.87	<0.0001
X 21	14.32	0.0018
X 22	6.88	0.0192
X 23	50.82	<0.0001
X 24	13.27	0.0024
X 1 X 2	1.46	0.2450
X 1 X 3	3.05	0.1010
X 1 X 4	0.035	0.8532
X 2 X 3	3.64	0.0756
X 2 X 4	5.99	0.0272
X 3 X 4	4.74	0.0458