The experimental variables and levels based on the CCD method.
Factors | Units | Level | Coded low | Coded high | Mean | Standard deviation | Relative standard deviation | ||
---|---|---|---|---|---|---|---|---|---|
Low | High | ||||||||
σ | X 1 | mN m−1 | 1.75 | 36.00 | −1 ↔ 1.75 | +1 ↔ 36.00 | 17.28 | 14.28 | 0.83 |
A f | X 2 | cm s−1 | 0.60 | 1.30 | −1 ↔ 0.60 | +1 ↔ 1.30 | 0.90 | 0.16 | 0.18 |
V c | X 3 | mm s−1 | 0.41 | 1.08 | −1 ↔ 0.41 | +1 ↔ 1.08 | 0.63 | 0.24 | 0.38 |
V d | X 4 | mm s−1 | 0.08 | 0.97 | −1 ↔ 0.08 | +1 ↔ 0.97 | 0.44 | 0.19 | 0.43 |