Table 4. Values of regression coefficients calculated for milk beverage supplemented with coffee

Independent variables	Regression coefficient	Standard error coefficient	t-value	Significance level (p)
Constant	84.7754	0.7376	115.562	0.000
Linear
X1	−7.2987	0.7213	−10.119	0.000
X2	−5.7655	0.7213	−7.994	0.000
Quadratic
X12	−1.6485	1.0631	−1.551	0.165
X22	0.8536	1.0631	0.803	0.448
Interaction
X1X2	−4.0429	0.8834	−4.577	0.003
r2	0.9644