Table 3.

Model validation metrics.

Model	% Variance explaineda	RMSEa	RMSEb	R2 b	MAEb	p valuec
Temperature	82.59	1.223	1.344	0.794	0.934	<0.001
pH	81.02	0.238	0.251	0.793	0.164	<0.001
Salinity	85.65	4.345	4.616	0.839	2.95	<0.001

Models were tested using a 20% withhold 10-fold cross-validation technique and the randomisation technique recommended by Murphy et al.⁷⁶ (see Methods for details).

RMSE root-mean square error, MAE mean absolute error.

^aCalculated from the “out-of-the-bag” predictions⁷⁴.

^bCalculated using 20% withhold 10-fold cross-validation⁷³.

^cCalculated using the randomisation technique⁷⁶.