Table 2.
Statistical measures of nitrate concentration of 5790 groundwater measurement sites and inverse distance weighted (IDW) interpolated concentrations for all sites in Bavaria (interpolated across the borders of the hydrogeological regions) and interpolated for the sites of the hydrogeological regions separately
| Statistical measures | Measurement sites | IDW interpolation | |
|---|---|---|---|
| All sites | HGR separately | ||
| Mean (mg NO3/l) | 16.62 | 16.22 | 16.34 |
| Minimum (mg NO3/l) | 0.00 | 0.03 | 0.03 |
| Maximum (mg NO3/l) | 395.0 | 269.7 | 269.7 |
| Standard deviation (mg NO3/l) | 19.30 | 15.98 | 16.40 |
| Mean absolute error (mg NO3/l) | 7.03 | 7.11 | |
| Correlation coefficient | 0.710 | 0.707 | |
| Number of sites with concentration above 50 mg NO3/l | 277 | 154 | 171 |
| -Percentage of true number | 55.6% | 61.7% | |