Table 8.
Logistic regression model results for predicting poor versus good macroinvertebrate MMI condition. The numbers in the table are the regression coefficients (odds ratios) for the significant predictor variables identified from the stepwise model selection process. Ecoregion codes are given in Table 1, variable codes are given in Table 2. Model R2 is McFaddens R2 for logistic regression.
| Variable | CPL | NAP | SAP | UMW | TPL | NPL | SPL | XER | WMT |
|---|---|---|---|---|---|---|---|---|---|
| TN | 15.9 | 6.63 | -- | 5.47 | -- | -- | -- | 5.68 | 7.23 |
| TP | -- | -- | -- | -- | -- | -- | 3.54 | -- | -- |
| CL | -- | -- | 2.94 | -- | -- | -- | -- | 2.57 | -- |
| SO4 | -- | -- | -- | -- | -- | -- | 2.96 | -- | -- |
| TURB | -- | 9.77 | 5.02 | 5.03 | 2.39 | -- | -- | -- | 3.17 |
| RIPCOV | -- | -- | -- | 9.46 | 4.58 | -- | -- | -- | -- |
| FINEPCT | 1.4 | -- | -- | -- | -- | 1.33 | -- | 1.52 | 2.21 |
| RBS | -- | 4.97 | 2.55 | -- | 2.44 | -- | -- | -- | -- |
| POPDEN | -- | 2.23 | -- | -- | 0.22 | -- | -- | -- | |
| ROADDEN | -- | -- | -- | -- | 2.80 | -- | -- | -- | -- |
| DAM | -- | -- | 1.15 | -- | -- | -- | 0.76 | 1.33 | 1.27 |
| ERODE | -- | -- | 3.29 | -- | -- | 6.69 | -- | -- | -- |
| Model R2 | 0.273 | 0.371 | 0.253 | 0.232 | 0.256 | 0.304 | 0.185 | 0.318 | 0.358 |