Table 3.

Coded (actual) levels of the operational parameters and observed values of BBD.

No.	Temperature (°C) (A)	Extraction Time (min) (B)	Solvent-to-Solid Ratio (mL/g) (C)	Rhein Content (mg/g Extract)
1	0 (50)	0 (15)	0 (30:1)	9.49
2	0 (50)	−1 (10)	−1 (20:1)	8.12
3	+1 (60)	−1 (10)	0 (30:1)	8.36
4	0 (50)	0 (15)	0 (30:1)	9.45
5	+1 (60)	+1 (20)	0 (30:1)	10.42
6	−1 (40)	+1 (20)	0 (30:1)	8.50
7	−1 (40)	−1 (10)	0 (30:1)	9.31
8	−1 (40)	0 (15)	+1 (40:1)	7.35
9	+1 (60)	0 (15)	+1 (40:1)	9.02
10	0 (50)	+1 (20)	+1 (40:1)	7.39
11	0 (50)	−1 (10)	+1 (40:1)	7.19
12	+1 (60)	0 (15)	−1 (20:1)	9.24
13	0 (50)	0 (15)	0 (30:1)	10.15
14	−1 (40)	0 (15)	−1 (20:1)	9.39
15	0 (50)	0 (15)	0 (30:1)	9.35
16	0 (50)	+1 (20)	−1 (20:1)	9.71
17	0 (50)	0 (15)	0 (30:1)	9.58