Table 3 Estimated effect, regression coefficient, and ANOVA of the Plackett-Burman matrix of different components for calcium chelation by demineralization process
Variables | Sum of squares | df | Coefficient | Mean squares | p value |
|---|---|---|---|---|---|
Model | 150,601.81 | 5 | Â | 30,120.36 | 0.0007 |
Temperature | 2043.63 | 1 | 13.05 | 2043.63 | 0.3002 |
Concentration | 142,179.87 | 1 | 108.85 | 142,179.87 | < 0.0001 |
pH | 270.75 | 1 | − 4.75 | 270.75 | 0.6960 |
Volume | 5967.48 | 1 | − 22.3 | 5967.48 | 0.0975 |
Time | 140.08 | 1 | 3.416667 | 140.08 | 0.7781 |
Curvature | 5449.85 | 1 | Â | 5449.85 | 0.1105 |
Lack of fit | 11,431.48 | 6 | Â | 23,815.5799 | 0.0050 |
Coefficient of determination (R2) = 0.93 | |||||