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 |