Table 2.

Sample correlations ($r_{{}_{(SI,i)}}$) of SI with all other variables, and estimates of the sample correlations according to four biplots. The bottom line gives the RMSE of SI for each method. For PCA, the RMSE calculation includes the correlation of SI with itself, for WALS, it does not.

		PCA		WALS
	$r_{{}_{(SI,i)}}$	$\delta =0$	$\delta =0.14$	$\delta =0$	$\delta =-0.27$
		$\mathbf{R}$	${\mathbf{R}}_{{}_a}$	$\mathbf{R}$	${\mathbf{R}}_{{}_a}$
Pulse	−0.503	−0.264	−0.316	−0.271	−0.340
CI	0.887	0.818	0.905	0.894	0.889
SI	1.000	0.814	1.017	0.842	0.557
DBP	−0.483	−0.609	−0.597	−0.514	−0.497
PA	−0.405	−0.544	−0.546	−0.440	−0.430
VP	−0.201	−0.416	−0.092	−0.252	−0.330
logPR	−0.833	−0.867	−0.717	−0.848	−0.823
RMSE (SI)		0.160	0.116	0.099	0.086