highly significantp = 0.002
Lastly, binned into broad ethnic categories for the sake of a correlation analysis (and due to the relatively small sample size, see Table 2 ), we observed a highly significant correlation between the ROI quality score and ethnic origin (tau = −0.391, p = 0.002), with sessions from subjects of ethnicities likely to have higher hair occlusion (according to self-reported responses averaged by ethnicity) also having lower ROI quality scores (see Figure 9 left bottom).