Absolute and Relative Dispersion

Dispersion is studied under two different methods viz. (i) absolute, and (ii) relative.

Under the absolute method, the dispersions are found out in the same unit in which the data are expressed. But this method of dispersion is not suitable for comparative study of the characters of two or more series. For this, relative dispersions of the comparable series are worked out .The relative dispersions are expressed in terms of ratios, or percentages and these are represented as co-efficients of dispersions.

Thus, the various types of dispersions that are mostly in use may be outlined as under:

• Range, and its co-efficient
• Inter-Quartile range, and its co-efficient
• Semi-inter Quartile range (Quartile Deviation), and its co-efficient.
• Decile range, and its co-efficient.
• Percentile range, and its co-efficient
• Mean Deviation, and its co-efficient
• Standard deviation, and its co-efficient
• Co-efficient of variation.
• Variance
• Lorenz curve.