Table 2. Results of modeling and optimization

A. Coefficient estimates in the heterogeneous 3rd–order model on Y1
Term	Parameter estimate	Standard error	t-value	p-value
Intercept	b0=182.99	2.76	66.24	<0.0001
X1	b1=–19.75	4.28	−4.62	0.0099
X2	b2=−1.58	4.28	−0.37	0.7302
X12	b11=−11.33	3.71	3.06	0.0378
X22	b22=−3.04	3.71	−0.82	0.4579
X1X2	b12=10.47	3.03	3.46	0.0258
X12X2	b112=11.23	5.24	2.14	0.0987
X1X22	b122=30.03	5.24	5.73	0.0046