As it has been pointed out earlier, there are different measures of dispersion with their relative merits and demerits. But the merits and demerits common to all types of measures of dispersion are outlined as under:
- They indicate the dispersal character of a statistical series.
- They speak of the reliability, or dependability of the average value of a series.
- They enable the statisticians for making a comparison between two or more statistical series with regard to the character of their stability or consistency.
- They facilitate in controlling the variability of a phenomenon under his purview.
- They facilitate in making further statistical analysis of the series through the devices like co-efficient of skewness, co-efficient of correlation, variance analysis etc.
- They supplement the measures of central tendency in finding out more and more information relating to the nature of a series.
- They are liable to misinterpretations, and wrong generalizations by a statistician of based character.
- They are liable to yield inappropriate results as there are different methods of calculating the dispersions.
- Exception on or two, of the methods of dispersion involve complicated process of computation.
- They may give a value of variation, which may not be practically found with the items of the series.
- They, by themselves, cannot give any idea about the symmetricity, or skewed character of a series.
- Like the measures of central tendency, most of the measures of dispersion do not give a convincing idea about a series to a layman.