DISPERSION * (also called variability, scatter, or spread) denotes how stretched or squeezed * Contrasted with location or central tendency and together they are the most used properties of distributions. * A quantifiable variation of measurements of differing members of a population.
Common examples of measures of statistical dispersion: * variance * standard deviation * interquartile range
Measures of statistical dispersion * A measure of statistical dispersion is a nonnegative real number that is zero if all the data are the same and increases as the data become more diverse.
If the measurements are in metres or seconds, so is the measure of dispersion. Such measures of dispersion include: * Standard deviation * Interquartile range * Range * Mean difference * Median absolute deviation * Average deviation * Distance standard deviation

Range * Is the simple measure of dispersion, which is defined as the difference between the largest value and the smallest value. Mathematically, the absolute and the relative measure of range can be written as the following:
R=L – S

Where R= Range. L= largest value, S= smallest value
Quartile deviation * This is a measure of dispersion. In this method, the difference between the upper quartile and lower quartile is taken is called the interquartile range. Symbolically it is as follows:

Mean deviation * Mean deviation is a measure of dispersion, which is known as the average deviation. Mean deviation can be computed from the mean or median. Mean deviation is the arithmetic deviation of different items of central tendency. It may be the mean or the median. Symbolically, mean deviation is defined as the following:

Where M= median, = mean
Standard deviation * In the measure of dispersion, the standard deviation method is the most widely used