Table 4.

Regression coefficient for main factors and their interaction

Terms	Factors/Interaction	Regression coefficient	Standard Error	t-Stat
β o	Mean/Intercept	19.889	1.125	17.686
β 1	Pressure (X 1)	−0.892	0.597	−1.495
β 2	Temperature (X 2)	0.042	0.597	0.070
β 3	Enzyme concentration (X 3)	0.543	0.597	0.910
β 4	pH (X 4)	0.771	0.597	1.291
β 5	Buffer (X 5)	−0.749	0.737	−1.017
β 11	Pressure (X 21)	−2.553	0.533	−4.794
β 22	Temperature (X 22)	−3.458	0.533	−6.493
β 33	Enzyme concentration (X 23)	−3.861	0.533	−7.251
β 44	pH (X 24)	−3.046	0.533	−5.721
β 55	Buffer (X 25)	−3.931	0.533	−7.383
β 12	X 1 X 2	1.418	1.062	1.335
β 13	X 1 X 3	0.841	1.118	0.753
β 14	X 1 X 4	−1.207	1.062	−1.137
β 15	X 1 X 5	1.807	0.804	2.247
β 23	X 2 X 3	−1.062	1.062	−1.000
β 24	X 2 X 4	2.525	0.989	2.554
β 25	X 2 X 5	−0.558	0.747	−0.748
β 34	X 3 X 4	1.036	1.062	0.975
β 35	X 3 X 5	−1.065	0.804	−1.324
β 45	X 4 X 5	−0.033	0.747	−0.044