Central composite design showing independent

Experiment	Level of Controlled variables in Coded Form		Absorbance of the supernatant at 280 nm	percentage of protein precipitated (w/w)	% w/v TCA
Experiment	X₁	X₂	Y₁	Y₂	% w/v TCA
1	-1	-1	0.033	84.1	2.00
2	-1	+1	0.062	81.67	5.77
3	+1	-1	0.067	66.15	1.35
4	+1	+1	0.049	92.67	3.95
5	-1.414	0	0.049	85.43	4.35
6	+1.414	0	0.037	89.74	2.50
7	0	-1.414	0.725	61.34	0.95
8	0	+1.414	0.065	82.16	5.30
9	0	0	0.049	80.2	3.18
10	0	0	0.054	82.11	3.18 1
11	0	0	0.052	82.01
12	0	0	0.046	75.14
13	0	0	0.049	83.10	3.18

¹4 replicates centers points

Table 2: Central composite design showing independent variables with measured responses.