In this article we will discuss about Mean Deviation:- 1. Meaning of Mean Deviation 2. Computation of Mean Deviation.
Meaning of Mean Deviation:
Deviation refers to the difference between the calculated means (arithmetic mean, median and mode) and the value of individual data. Mean deviation is the mean of the deviations of all data of a series from the real mean value.
Theoretically, the mean deviation is a true measure of dispersion. In the calculation of mean deviation all the values (+ and -) of deviation are taken as positive. When the mean deviation is divided by the mean of the series, the value so obtained is called co-efficient of mean deviation.
Computation of Mean Deviation:
2. When the data are ungrouped and tabulated:
The mean deviation of ungrouped data is calculated with the help of the following formulae:
3. When Data are Classified and Tabulated:
The mean deviation of Tabulated and Classified data is also calculated with the help of same formulae as are used for ungrouped data: