It's deviations from the mean, so if the deviation were "3" for example, values of 6, 3, 0, -3 and -6 would be 2, 1, 0, -1, and -2 deviations away from the central line, respectively.
It's deviations from the mean, so if the deviation were "3" for example, values of 6, 3, 0, -3 and -6 would be 2, 1, 0, -1, and -2 deviations away from the central line, respectively.