Table 3 Analysis of variance for the experimental results of zerumbone content from Z. zerumbet rhizomes
Parameter | Estimated coefficient | Standard error | Degree of freedom | Sum of squares | F value | Prob > F |
|---|---|---|---|---|---|---|
Model intercept B0 | 5.51 | 0.084 | 14 | 3.95 | 13.38 | 0.0001 |
Linear | ||||||
X1 | 0.14 | 0.042 | 1 | 0.25 | 11.74 | 0.005 |
X2 | 0.017 | 0.042 | 1 | 0.00343 | 0.16 | 0.693 |
X3 | −0.055 | 0.042 | 1 | 0.037 | 1.77 | 0.211 |
X4 | 0.27 | 0.042 | 1 | 0.085 | 40.46 | 0.0001 |
Quadratic | ||||||
\(X_{1}^{2}\) | −0.41 | 0.063 | 1 | 0.89 | 42.02 | 0.0001 |
\(X_{2}^{2}\) | −0.096 | 0.063 | 1 | 0.05 | 2.35 | 0.1513 |
\(X_{3}^{2}\) | −0.085 | 0.063 | 1 | 0.039 | 1.84 | 0.2001 |
\(X_{4}^{2}\) | −0.39 | 0.063 | 1 | 0.081 | 38.52 | 0.0001 |
Interaction | ||||||
X1X2 | 0.12 | 0.073 | 1 | 0.057 | 2.71 | 0.1259 |
X1X3 | 0.14 | 0.073 | 1 | 0.079 | 3.74 | 0.077 |
X1X4 | −0.31 | 0.073 | 1 | 0.039 | 18.45 | 0.001 |
X2X3 | 0.45 | 0.073 | 1 | 0.08 | 37.78 | 0.0001 |
X2X4 | −0.13 | 0.073 | 1 | 0.072 | 3.42 | 0.0894 |
X3X4 | −0.061 | 0.073 | 1 | 0.015 | 0.69 | 0.4212 |
Lack of fit | 10 | 0.23 | 2.15 | 0.3596 | ||
Pure error | 2 | 0.022 | ||||
Residual | 12 | 0.025 | ||||
R2 adjusted | 0.875 | |||||
R2 | 0.939 | |||||
C.V.% | 2.86 | |||||
Corr. total | 26 | 4.21 | ||||