What is Mean Deviation

Introduction to mean deviation:

The difference between observed value and the expected value of a function is called mean deviation. The mean deviation is the mean of the absolute deviation of a set of data about the data's mean. It is an important expressive statistic that is not frequently used in mathematical statistics. This is basically mean deviation as the "mean deviation from the mean," the introduction of the complete value makes logical calculations using this statistic much more difficult.

Mean Deviation

In order to find the dispersion of values of x from a central value ‘a’, we find the deviations about a. To calculate the mean need know the sum of the deviations. And number of observations.

Also mean of deviations = Sum of deviations/ Number of observations

This will also help us on factorising.Find the mean of deviations about mean is not of any use , as far as the measure of dispersion is concerned. Remember find a suitable measure of dispersion, we require the distance of each value from a central tendency or a fixed number ‘a’.