Table 4.
Analysis of experiment (ANOVA) by using Statistica 13.
| Effect/Factor | Analysis of Variance, Mean = −15.9350, Sigma = 4.2932 | ||||
|---|---|---|---|---|---|
| SS | df | MS | F | p | |
| Repetition | 0.0180 | 2 | 0.0090 | 0.646 | 0.5569 |
| pH | 95.6632 | 1 | 95.6632 | 6855.424 | <0.05 |
| K2FeO4 | 51.8397 | 1 | 51.8396 | 3714.937 | <0.05 |
| Time | 55.1406 | 1 | 55.1405 | 3951.489 | <0.05 |
| Error | 0.0837 | 6 | 0.0136 | – | – |
Mean—mean of ETA-value, Sigma—population standard deviation, SS—sum of squares, MS—mean square error, F—statistics, df—number of degrees of freedom, p—statistically significant if p < 0.05.