Table 4.
ANOVA table for quadratic response surface design
| Source | Coefficient | Sum of squares | df | Mean of squares | F-value | P-value |
|---|---|---|---|---|---|---|
| Intercept | 182.761 | |||||
| P | −8.8733 | 27.00 | 1 | 27.00 | 406.0 | <0.0001 |
| S | 0.0934 | 1.77 | 1 | 1.77 | 26.66 | 0.0004 |
| A | −1.5232 | 1.00 | 1 | 1.00 | 15.05 | 0.0031 |
| P2 | 0.1227 | 8.48 | 1 | 8.48 | 127.49 | <0.0001 |
| S2 | 0.0012 | 8.05 | 1 | 8.05 | 121.11 | <0.0001 |
| A2 | 0.0091 | 1.56 | 1 | 1.56 | 23.40 | 0.0007 |
| P × S | −0.0078 | 1.91 | 1 | 1.91 | 28.74 | 0.0003 |
| P × A | 0.0265 | 1.27 | 1 | 1.27 | 19.13 | 0.0014 |
| S × A | −0.0015 | 0.42 | 1 | 0.42 | 6.30 | 0.0310 |
| Model | 48.95 | 9 | 5.44 | 81.80 | <0.0001 (significant) | |
| Residual | 0.66 | 10 | 0.07 | |||
| Lack of fit | 0.27 | 5 | 0.05 | 0.68 | 0.6585 (not significant) | |
| Pure error | 0.40 | 5 | 0.08 | |||
| Corrected total | 49.61 | 19 | ||||
| R3 | 0.986 | |||||
| Adjusted R3 | 0.972 | |||||
| Predicted R3 | 0.942 | |||||
| Adequate precision | 28.47 |
Abbreviations: A, primary gas flow rate (L/min); ANOVA, analysis of variance; df, degrees of freedom; P, input power (Kw); S, spraying distance (mm).