Measure of Spread

The range

The range is one of the ways to measure how spread out the numbers are.

The range is the difference between the highest and lowest numbers.

Here are Kieran's results again:

10, 14, 10, 12, 11, 10, 11, 12, 10, 11, 9 and 12.

Kieran's highest number is 14, and the lowest 9.

Therefore, the range is 14 - 9 = 5.

To find the range of a set of numbers, you need to:

  • find the lowest number
  • find the highest number
  • subtract the lowest number from the highest number
  • know that the difference between the highest and lowest number is called the range
Question

What is the range of this set of numbers?

5, 8, 3, 6, 2, 8, 6, 9, 3

Lowest number = 2

Highest number = 9

Range = 9 – 2 =7