Question

any one know how to solve deviation method

Answer 1

In statistics the assumed mean is a method for calculating the arithmetic mean and standard deviation of a data set. It simplifies calculating accurate values by hand. Its interest today is chiefly historical but it can be used to quickly estimate these statistics.

Answer 2

Step-deviation Method. When the values of the mid-values xi in the different classes of a grouped data are large in magnitude, then the computation of the mean x becomes quite lengthy and tedious. In such a case, computation is simplified by 'short-cut method'.          

This method is nothing but an extension of the shortcut method explained above. When the figures of deviations appear to be big, and divisible by a common factor, this method, the figures of deviations are reduced by dividing them all by a common factor. The formulas are thus modified as under:

Step Deviation Method of Mean

Where,  c = Common factor by which each of the deviations is divided

d1 = the deviation from the assumed average divided by the common factor i.e., X-A/C

All other factors import the same meaning cited as before.