The detailed procedure of finding the Mean Deviation under the different models from different types of series are discussed in the following paragraphs. Model from different types of series are discussed in the following paragraphs.
In case of individual series
For computing the mean deviation from an individual series, the following steps are to be taken up in turn.
(1) Determine the value of the required average
(2) Find the deviations of the items from such average ignoring the + and – sings and get them totaled as ∑D or ∑X – X – X
(3) Put the relevant formula as cited before viz. = ∑D/N , and get the results of absolute M.D.
(4) Divide the M.D. by the average concerned to get the co-efficient of Mean Deviation.