How to find Mean Deviation!

The mean deviation of a statistical data is defined as the arithmetic mean of the numerical values of the deviations of items from some average value.

Mean deviation is also known as average deviation.

The mean deviation is generally denoted by M.D.

Formula for mean deviation for ungrouped data or an individual series is given by

For a frequency distribution, the formula for mean deviation is given by

where M.D is the Mean Deviation and A.M is the Arithmetic Mean.

Example 1:

Find the mean deviation from the mean for the given raw data

12,6,7,3,15,10,18,5.

Suggested answer:

Example 2:

Calculate the mean deviation from the mean for the following frequency distribution.

Suggested answer:

Let us first find the mean of the given data by step deviation method.

A = Assumed mean = 57.5, h = 5

\ M = 52

Mean deviation from the mean