Method of Calculation of Mean Deviation
a.Computation of Mean Deviation Individual Series : The process of computing mean deviation in case of individual series involves the followings steps.
a.Calculate the average mean median mo mode of the series.
b.Take the deviations of items from average ignoring + and - sings and denote these deviations by | d| .
c.Compute the total of these deviation i, e, ∑ |d|
d.Divide this total obtained by the number of items.
Symbolically
Mean Deviation = ∑|d|/ n
Where |d| = deviation from mean ( or median) ignoring+ sings
N = number of items.