The range of a data set is calculated as the difference between the highest and the lowest value in the data set. The range of a data set thus describes how wide the interval is within which the values of the data set falls.
Using a functional notation the formal definition of range is:
range(data) = max(data) - min(data)
To see how to calculate the range of a data set, look at this example data set:
1, 2, 3, 3, 3, 2, 4, 8, 1, 8, 3, 9, 3
The highest value in this data set is 9 and the lowest value is 1. The range is thus defined as:
Using the functional notation from above, range would be calculated like this:
range(data) = max(data) - min(data) range(data) = 9 - 1 range(data) = 8
The range of the example data set is thus 8.