Fig. 6

Feature importance by Lasso regularised logistic regression. Importance is measured using the absolute values of the standardised logistic regression coefficients, averaged across the fivefold cross-validation. Error bars are standard deviations across the fivefold cross-validation. Selected features had mean Importance > 0.03 (threshold determined by cross-validation). WPT-HR: wavelet packet transform of HR; WPT-Acc: wavelet packet transform of Acc; LSW-HR-Acc: local stationary wavelet estimated coherence between HR and Acc. In these cases, each bar corresponds to a frequency band.