This document discusses measures of dispersion, or variation, in data sets. It describes absolute and relative measures of dispersion. Absolute measures give the dispersion in the same units as the original data but cannot be used to compare different data sets. Relative measures are dimensionless and can be used to compare dispersion across data sets. The document then discusses the range as the simplest measure of absolute dispersion. The range is defined as the difference between the maximum and minimum values in a data set. It also defines the coefficient of range, which normalizes the range as a percentage to allow comparison between data sets. Two examples are given to demonstrate calculating the range and coefficient of range.