Table 2.

Central composite design matrix of variables

Run order	Coded values			Actual values
	A	B	C	A	B	C
1	2	0	0	4.85	132.50	20.0
2	1	−1	1	4.00	125.00	10.0
3	0	−2	0	2.75	119.89	20.0
4	1	1	−1	4.00	140.00	10.0
5	0	−2	0	2.75	119.89	20.0
6	1	1	1	4.00	140.00	30.0
7	−1	−1	−1	1.50	125.00	10.0
8	0	0	0	2.75	132.50	20.0
9	−1	−1	1	1.50	125.00	30.0
10	0	−1	0	2.75	125.00	20.0
11	0	0	0	2.75	132.50	20.0
12	0	2	0	2.75	145.11	20.0
13	0	0	2	2.75	132.50	36.82
14	0	0	0	2.75	132.50	20.00
15	1	−1	1	4.00	125.00	30.00
16	0	0	0	2.75	132.50	20.00
17	−1	1	1	1.50	140.00	30.00
18	−2	0	0	0.65	132.50	20.00
19	−1	1	−1	1.50	140.00	10.00
20	0	0	−2	2.75	132.50	3.18