Merits and Demerits of Mean Deviation

Introduction:

Today graphics, tables, reasoning, estimation and prediction are playing a very important role in stating the facts in terms of figures.

Statistics deals mainly in communicating facts and figures in terms of a method called statistical method. Collection, classification, tabulation, representation, reasoning, testing and drawing inferences are part of statistical methods.

The word statistics is used with two meanings. 1. Systematically collected and presented numerical data. 2. Processing the numerical data and to draw conclusions from there.

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.

Merits and Demerits of Mean Deviation:

Merits:

1. Mean deviation is easy to calculate. This measure is simple to understand.

2. This can be calculated from any average.

3. It is less affected by extreme observations.

Demerits:

1. This is mathematically incomplete because it ignores negative signs.

2. As it can be calculated from any average, it does not have certainty (i.e., it is not a well defined measure).

3. Its use is very limited in statistical work.