Table 4.

Actual and predicted values for ethanol concentration (g/L) and productivity (g/L/hr) based on Box–Behnken design

Runs	Codes			Ethanol concentration			Ethanol productivity
	X1	X2	X3	Observed	Predicted	Residual	Observed	Predicted	Residual
1	30	2	4	69.25	71.38	− 2.13	4.33	4.47	− 0.14
2	20	0.5	5	9.61	11.38	− 1.77	1.72	1.87	− 0.15
3	30	0.5	6	76.51	74.39	2.12	4.78	4.64	− 0.14
4	20	1.25	6	16.21	16.57	− 0.36	2.36	2.38	0.00
5	30	1.25	5	69.82	71.12	− 1.30	4.36	4.44	− 0.08
6	30	1.25	5	71.12	71.12	0.00	4.44	4.44	− 0.00
7	20	2	5	15.00	14.35	0.65	2.34	2.27	0.07
8	40	0.5	5	72.47	73.13	− 0.65	4.53	4.60	0.09
9	30	1.25	5	72.42	71.12	1.30	4.53	4.44	− 0.07
10	40	1.25	6	72.31	73.78	− 1.47	4.52	4.59	0.08
11	20	1.25	4	14.12	12.77	1.47	2.08	2.01	0.15
12	30	0.5	4	69.64	69.35	0.29	4.35	4.28	− 0.00
13	40	2	5	71.14	69.38	1.76	4.44	4.29	− 0.08
14	40	1.25	4	72.70	72.34	0.36	4.54	4.55	− 0.01
15	30	2	6	71.28	71.58	− 0.29	4.46	4.54	− 0.08