Measures of Dispersion are the measure of the extent to which observations in a data set are close or far away from any given measure of central tendency. They are representative of homogeneity or heterogeneity of a distribution. The closer are the observations from their given central tendency, the more homogeneous is the distribution. The farther the observations from their data, the more heterogeneous is the distribution of the population.
There are many measures of dispersion. Some frequently used measures are given below:
- Quartile Deviation
- Mean Deviation
- Standard Deviation
From the above measures of dispersion Standard Deviation will be frequently used. There will be separate notes on this topic.
For a detailed reading of measures of dispersion, you should consult Fundamentals of Mathematical Statistics by S. C. Gupta and V. K. Kapoor. This book is a standard book on statistics for any postgraduate exam in Indian Universities.