The standard deviation is a measure of dispersion. It is the action or process of distributing thing over a wide area. Dispersion: dispersion is the measure of the variation between items. ● Dispersion is the state of getting dispersed or spread. Statistical dispersion means the extent to which a numerical data is likely to vary about an average value. ● In other words, dispersion helps to understand the distribution of the data. Central tendency: A measure of central tendency is a typical value for a probability distribution. ● It is calculated for a grouped data or for a probability distribution. ● The most common measure of central tendency are mean, median and mode.