Performance Optimization, Prediction, and Adequacy by Response Surfaces Methodology with Allusion to DRF Technique

Table 2

Actual and coded values for independent variables and experimental design.

Sample code	Levels of variables
	𝑋1 Wool fibre length (mm)		𝑋2 Twist multiplier		𝑋3 Strand spacing (mm)
	Coded	Actual	Coded	Actual	Coded	Actual
1	−1	65	−1	2.00	0	14
2	1	75	−1	2.00	0	14
3	−1	65	1	2.50	0	14
4	+1	75	1	2.50	0	14
5	0	70	0	2.25	0	14
6	−1	65	0	2.25	−1	10
7	+1	75	0	2.25	−1	10
8	−1	65	0	2.25	+1	18
9	+1	75	0	2.25	+1	18
10	0	70	0	2.25	0	14
11	0	70	−1	2.00	−1	10
12	0	70	1	2.50	−1	10
13	0	70	−1	2.00	+1	18
14	0	70	+1	2.50	+1	18
15	0	70	0	2.25	0	14