Fig. 2: Principal component analysis.
From: Evaluation of physical health status beyond daily step count using a wearable activity sensor
a PCA scatter plot of the first two principal components. For each subject (N = 20), 10 weeks were randomly selected from the dataset. The variance for the first two principal components were 48.6% and 30.0%, respectively. For 100 independent runs, the mean variance of PC1 and PC2 was 77.5 ± 0.58%. Numbers represent subject IDs. Each point represents one week of data. b Loading plot. HR(SR = 0):mean is the mean value of the heart rate at SR = 0; HR(SR > 0):SD is the standard deviation of the heart rate at SR > 0; SR(SR > 0):mean is the mean step count for SR>0; SR(SR>0):SD is the standard deviation of the step rate for SR > 0; time active is the fraction of minutes with SR = 0.
