Table 2.

Results of multiple linear regression parameter estimations

Variables	Coefficient	Standard error	t	95% CI	P
Guangdong Province
Intercept (β0)	87.46	14.77	5.92	55.29 to 119.64	< 0.001
Time (β1)	5.52	2.62	2.11	− 0.19 to 11.23	0.057
Intervention (β2)	− 41.50	11.77	− 3.52	− 67.14 to − 15.85	0.004
Post-time (β3)	− 18.18	3.41	− 5.33	− 25.62 to − 10.75	< 0.001
PRD region
Intercept (β0)	248.47	48.18	5.16	143.50 to 353.45	< 0.001
Time (β1)	− 3.38	8.67	− 0.39	− 22.28 to 15.51	0.703
Intervention (β2)	− 104.22	33.13	− 3.15	− 176.39 to − 32.04	0.008
Post-time (β3)	− 14.47	48.18	− 1.57	− 34.60 to 5.65	0.143
Eastern and Western wings
Intercept (β0)	9.81	4.40	2.23	0.22 to 19.39	0.046
Time (β1)	4.44	1.14	3.89	1.95 to 6.93	0.002
Intervention (β2)	10.94	6.29	1.74	− 2.76 to 24.65	0.107
Post-time (β3)	− 10.49	1.21	− 8.67	− 13.13 to − 7.86	< 0.001
North ecological development zone
Intercept (β0)	19.19	6.31	3.04	5.43 to 32.94	0.010
Time (β1)	16.91	2.01	8.40	12.52 to 21.29	< 0.001
Intervention (β2)	− 45.54	15.07	− 3.02	− 78.39 to − 12.68	0.011
Post-time (β3)	− 32.88	4.03	− 8.15	− 41.67 to − 24.09	< 0.001