Measures of Dispersion for Ungrouped Data
Range
The difference between the largest and smallest values in a data set.
| English | Range |
|---|---|
| Bahasa Melayu | Julat |
| 中文 | 全距 |
How it is used
For the daily temperatures 28, 30, 31, 33 and 35 °C, the range is 35 − 28 = 7 °C, the gap between the hottest and coolest readings.
Where it shows up in SPM
In Measures of Dispersion for ungrouped data as the simplest measure of spread. Paper 1 uses it for a fast one-mark answer; Paper 2 uses it as a first comparison before the more informative standard deviation.
Don't confuse it with
Open the chapter: Measures of Dispersion for Ungrouped Data →
Frequently asked questions
How do I calculate the range?
Subtract the smallest value from the largest. You do not need to order the whole list; you only need to identify the maximum and minimum.
For 28, 30, 31, 33, 35 the maximum is 35 and the minimum is 28, so the range is 7.
Why is the range called a weak measure of spread?
Because it depends on just two values and ignores everything in between. Two data sets can share the same range yet be spread very differently, so the standard deviation or interquartile range usually gives a more reliable picture.