Variance/Variability On the variability page of the TQ assessment, the coefficient of variability is the Variance (standard deviation squared) divided by the mean. It shows the number of times that variance is greater than the average, so a higher number means a much more spread-out distribution–less effective control of brain activity in that area and in that frequency. Variability in one frequency doesn’t necessarily have any relationship to variability at others, so if beta for example is surging, that doesn’t […]