The following measures of absolute dispersion are in common use :
1) Based on selected items of the data
i) Range - spread for entire data
ii) Inter Quartile Range - spread for middle 50% data. More commonly Quartile Deviation is used in its place, which is half of inter quartile range.
2) Based on all items of the data
i) Mean Deviation - mean of the absolute deviations from central tendency.
ii) Standard Deviation or Root Mean Square Deviation about arithmetic mean
3) A Graphic Method - Lorenz Curve (This, however, is not a part of discussion in this course).
The relative measures of dispersion corresponding to the measures of absolute dispersion are :
| | Absolute Measures of Dispersion | Relative Measures of Dispersion |
| i) | Range | Coefficient of Range |
| ii) | Quartile Deviation | Coefficient of Quartile Deviation |
| iii) | Mean Deviation | Coefficient of Mean Deviation |
| iv) | Standard Deviation | Coefficient of Standard Deviation |
