Excess variance in the soft (3–10 keV) versus the excess variance in the full (3–79 keV) NuSTAR bands (left). All excess variances are normalized at 10 ks. The best-fit line is fully consistent with the bisector at 90% confidence level, with an angular coefficient of 0.96 ± 0.05. The correlation coefficient is r = 0.95 with a negligible or null probability. Excess variance in the soft band vs. excess variance in the hard (10–40 keV) X-ray band (right). The best-fit angular coefficient is 0.7 ± 0.1 with a correlation coefficient r = 0.90 and a negligible probability of finding the correlation by chance.