Table 9.
Analysis of variance with regression model of different response surfaces.
| Source | Quadratic sum | Degree of freedom | Mean square | F value | P value | |
|---|---|---|---|---|---|---|
| 3-day compressive strength | model | 8.02 | 5 | 1.60 | 49.43 | 0.0044 |
| A | 5.59 | 1 | 5.59 | 172.04 | 0.0010 | |
| B | 1.14 | 1 | 1.14 | 35.16 | 0.0096 | |
| AB | 0.5693 | 1 | 0.5693 | 17.53 | 0.0248 | |
| A2 | 0.6825 | 1 | 0.6825 | 21.02 | 0.0195 | |
| B2 | 0.0457 | 1 | 0.0457 | 1.41 | 0.3208 | |
| 7-day compressive strength | model | 14.72 | 5 | 2.94 | 169.47 | 0.0007 |
| A | 12.12 | 1 | 12.12 | 697.73 | 0.0001 | |
| B | 1.61 | 1 | 1.61 | 92.81 | 0.0024 | |
| AB | 0.5077 | 1 | 0.5077 | 29.23 | 0.0124 | |
| A2 | 0.4560 | 1 | 0.4560 | 26.26 | 0.0144 | |
| B2 | 0.0233 | 1 | 0.0233 | 1.34 | 0.3304 | |
| 28-day compressive strength | model | 19.4 | 5 | 4.85 | 110.18 | 0.0002 |
| A | 16.57 | 1 | 16.57 | 376.50 | < 0.0001 | |
| B | 2.09 | 1 | 2.09 | 47.46 | 0.0023 | |
| AB | 0.3528 | 1 | 0.3528 | 8.02 | 0.0473 | |
| A2 | 0.3851 | 1 | 0.3851 | 8.75 | 0.0416 | |
| B2 | 0.0819 | 1 | 0.0819 | 2.61 | 0.2047 |