Mean Deviation

Also known as the average deviation or mean absolute deviation.
This is a measure of how much on average the values differ from the mean.
This is the mean of the deviations from the mean
This indicates how much the scores differ from the central point (i.e. the mean)
This is rarely used as a measure of dispersion

This is also known as "the mean of the deviations from the mean".
This is rarely used as a measure of dispersion since it ignores the signs and just takes the absolute deviation.

For more examples of this function please refer to the AVEDEV page.

SS list of values - calculating the average deviation