mean deviation

the mean of the absolute deviations of the scores from the mean. For example, the mean deviation of the scores of 2 and 6 is the sum of their absolute deviations from their mean of 3.00 which is 2.00 [(4 – 3.00 = 1.00) + (2 – 3.00 =-1.00) = 2.00] divided by the number of absolute deviations which is 2. The mean deviation of these two deviations is 1.00 (2.00/2 = 1.00). The mean deviation is not very widely used in statistics simply because the related concept of standard deviation is far more useful in practice.

Table M.2 Table M.1 recast in terms of changing