Range
The range is the simplest measure of spread: the highest value in a data set minus the lowest. It uses only two observations and is highly sensitive to outliers.
What it is
See it move
Six branches report weekly sales from €9,800 to €21,000. The range is simply the gap between these two extremes: €21,000 − €9,800 = €11,200. It says nothing about the four branches in between, and a single unusual week at either extreme can swing this figure sharply, since only two data points feed it.
The formula
Variables
- Largest value in the data set
- Smallest value in the data set
The simplest measure of spread; based on only the two most extreme observations in the data set.
Check yourself
A quality control analyst records the diameter, in mm, of 5 sampled bolts: 12.02, 11.98, 12.10, 11.95, and 12.50 (the last one is a defective bolt). What is the range of these diameters?