Table 3.

Regression analysis of COD and NH₃-N pollutants

Station	COD							NH3-N
	Const	β T	β Q	F sig	R 2adj	VIF	Cl	Const	β T	β Q	F sig	R 2adj	VIF	Cl
Baidukou	1.5627	− 0.0020	− 0.0017	0.01	0.28	1.01	4.89	1.0625	− 0.0104	− 0.0078	0.01	0.40	1.01	4.89
Zhifang	1.2708	− 0.0014	0.0015	0.01	0.17	1.08	4.09	0.2282	− 0.0067	−0.0125	0.01	0.15	1.08	4.09
Chengwan	1.2321	−0.0032	–	0.60	0.04	1.12	4.33	0.1321	− 0.0391	0.001	0.01	0.38	1.12	4.87
Lifen	1.3748	–	− 0.0012	0.02	0.01	1.00	2.94	–	–	–	–	–	–	–
Zhidian	1.3933	−0.0030	− 0.0004	0.01	0.17	1.24	4.85	0.603	− 0.0190	− 0.0005	0.01	0.50	1.24	4.85

Estimated coefficients (Const: constant intercept, ${\mathit{\beta }}_T$: water temperature, ${\mathit{\beta }}_Q$: water discharge) in bolditalic or italic mean 0.05 or 0.10 significant level of t test). $F_{sig}$ and $R_{adj}^2$ are the significant level of F test and determination coefficient for the estimated model. VIF and Cl are variance inflation factor and maximum condition index