Table 2 Plackett–Burman design matrix for seven variables with coded levels
Trial | Starch | KNO3 | K2HPO4 | MgSO4 | FeSO4 | Casein | CaCO3 | Pig. conc (g/L) | Percentage of improvement in pigment production (%) |
|---|---|---|---|---|---|---|---|---|---|
1 | −1 | −1 | −1 | 1 | 1 | 1 | −1 | 0.0241 | 145.9 |
2 | 1 | −1 | −1 | −1 | −1 | 1 | 1 | 0.0202 | 106.1 |
3 | −1 | 1 | −1 | −1 | 1 | −1 | 1 | 0.0103 | 5.1 |
4 | 1 | 1 | −1 | 1 | −1 | −1 | −1 | 0.0012 | −87.8 |
5 | −1 | −1 | 1 | 1 | −1 | −1 | 1 | 0.0026 | −73.5 |
6 | 1 | −1 | 1 | −1 | 1 | −1 | −1 | 0.0096 | −2.0 |
7 | −1 | 1 | 1 | −1 | −1 | 1 | −1 | 0.0085 | −13.3 |
8 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0.0125 | 27.6 |
9 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0.0098 | 0.0 |