Tukey mean-difference plot of univariate and multivariate feature importance (left) and correlation of the importance measures shown in Fig. 3A. Horizontal lines in the left Fig. indicate differences of more than two sigma, the vertical line in the right Fig. indicates a threshold on the univariate P-value of 0.05 (with relevant features being to the right of the vertical line). -. The importances assigned by univariate and multivariate measures are generally highly correlated; many of the features marked in red (corresponding to the spectral channels indicated in Fig. 3B), however, are flagged as uninformative by a univariate measure and as relevant by a multivariate measure.