Table 4.
Regression coefficients and their significance of the quadratic model of optimization of size of biosynthesized gold nanoparticles.
| Model term | Coefficient estimate | Degree of freedom | Standard error | Probability (p) F |
|---|---|---|---|---|
| Intercept | +103.00 | 1 | 0.58 | 0.0004 |
| X1a | −40.75 | 1 | 0.50 | 0.0002 |
| X2 | +25.50 | 1 | 0.50 | 0.0004 |
| X3 | +17.50 | 1 | 0.50 | 0.0008 |
| X1X2 | −32.00 | 1 | 0.50 | 0.0002 |
| X1X3 | −31.75 | 1 | 0.50 | 0.0002 |
| X2X3 | −21.50 | 1 | 0.50 | 0.0005 |
| X12 | +1.13 | 1 | 0.52 | 0.1632 |
| X22 | +49.87 | 1 | 0.52 | 0.0001 |
| X32 | +28.63 | 1 | 0.52 | 0.0003 |
| X12X2 | −7.00 | 1 | 0.71 | 0.0101 |
| X12X3 | −24.75 | 1 | 0.71 | 0.0008 |
| X1X22 | +42.25 | 1 | 0.71 | 0.0003 |
a
X1, X2 and X3 refer to pH of medium, concentration of AuCl4 (mM) and temperature of shaker incubator (°C), respectively.