Table 6 Evaluation metrics of the soil EC prediction model.

R²

\(1-\frac{{\sum }_{i=1}^{m}{\left({y}_{i}-{\hat{y}}_{i}\right)}^{2}}{{\sum }_{i=1}^{m}{\left({y}_{i}-\bar{y}\right)}^{2}}\)

RMSE

\(\sqrt{\frac{1}{m}{\sum }_{i=1}^{m}{\left({y}_{i}-{\hat{y}}_{i}\right)}^{2}}\)

MSE

\(\frac{1}{m}{\sum }_{i=1}^{m}{\left({y}_{i}-{\hat{y}}_{i}\right)}^{2}\)

MAE

\(\frac{1}{m}{\sum }_{i=1}^{m}\left|{y}_{i}-{\hat{y}}_{i}\right|\)