. 2020 Mar 15;10(3):491. doi: 10.3390/ani10030491

Table 4.

Chow test analysis of WQ index score, total cost, and profit.

WQ	Coef.	Std.Err.	t	p > t	[95%Conf.Interval]
Total cost	29.27	0.451	64.9	0.000 ***	28.368	30.172
d1 ¹	568.931	170.503	3.34	0.001 ***	227.989	909.873
d2 ¹	644.561	110.42	5.84	0.000 ***	423.763	865.359
Total cost d1	−24.701	6.387	−3.87	0.000 ***	−37.472	−11.931
Total cost d2	−28.362	3.991	−7.11	0.000 ***	−36.342	−20.382
Profit	−166.017	19.9	−8.34	0.0000 ***	−205.81	−126.224
d3 ²	675.224	69.67	9.69	0.0000 ***	535.918	814.529
d4 ²	652.614	57.13	11.42	0.0000 ***	538.379	766.849
Profit d3	181.66	57.38	3.17	0.0020 ***	66.922	296.398
Profit d4	178.559	40.074	4.46	0.0000 ***	98.426	258.692

*** denote p < 0.01, d1 and d2 are two dummy variables in model 1, if d1_i = 0 and d2_i = 0, system = normal floor system (NFS), if d1_i = 1 and d2_i = 0, system = normal cage system (NCS), and if d1_i = 0 and d2_i = 1, system = high standard cage system (HCS). ² d3 and d4 are two dummy variables in model 2, if d3_i = 0 and d4_i = 0, system = normal floor system (NFS), if d3_i = 1 and d4_i = 0, system = normal cage system (NCS), and if d3_i = 0 and d4_i = 1, system = high standard cage system (HCS).