There are various methods of measuring the dispersions of a series which can be broadly classified into three categories as under:

- Method of limits
- Method of computations
- Method of graphs.

**1. Dispersion by the method of limits**

Under this method, the dispersion of a series are studied by taking into account the extreme limits of certain factors viz. value, quartiles, deciles, percentiles etc. of a series.

The following measures of dispersion come under this method : (i) Range, (ii) Inter-Quartile Range (iii) Semi-inter Quartile Range or Quartile Deviation, (iV) Decile Range, and (v) Percentile Range.

**2. Dispersion by the method of computation**

Under this method, the dispersal character of a series is studied through the process of computation. The following measures come under this calss:

**3.Dispersion by the method of graphs**

Under this method, the dispersion of a series is studied by drawing certain suitable, graphs, viz. Lorenz Curve: