Table 3.

Statistical summary and model performance parameters of spatial interpolation model

Statistics measured	Interpolation methods (unit : ppb)
	IDW	Kriging
Mean	108.25	99.7
95% Confidence Interval for Mean	108.1-108.4	99.5-99.8
Median	109.42	98.42
Std. Deviation	12.03	14.17
Minimum	58.94	68.84
Maximum	169.62	131.42
Correlation coefficients (P-value))	0.272 (0.051)	0.50* (0.00)
MAE	20.25	17.9
RMSE	25.13	22.58

^*Note. Correlation is significant at the 0.01 level (2-tailed).