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Concepts and Definitions 

The range is the most basic measure of the spread of a set of data. It is computed by taking the difference of the maximum and minimum value in the set of data.

Other than expressing the range as the difference between the maximum and minimum value, people may find it useful to illustrate the range by indicating its minimum and maximum value, for example:
imas  The unemployment rate ranged from 2.1% to 2.3% in 2010. 
imas  The median gross monthly income ranged from $1,200 for those with no formal qualification/lower primary qualifications to $5,417 for degree holders
 

How to calculate the range for a set of data?

Step 1: Identify the maximum and minimum value in the set of data
 
Step 2: Compute the range by taking the difference between the maximum and minimum value, i.e.
 

 
Example 1

Suppose there are 10 workers in company X, and their income levels are as follows:
$2,000; $3,000; $4,000; $5,000; $6,000; $7,000; $8,000; $9,000; $10,000; $11,000
 
The lowest income level for these 10 workers is $2,000, while the highest income level is $11,000.
 
Hence the income range for workers in company X = $11,000 – $2,000 = $9,000

Income of Workers in Company X
  
Example 2

Suppose we want to compare the range in the quarterly seasonally adjusted overall unemployment rate in 2009 with that in 2010.
 
For 2009, the highest unemployment rate was 3.3% (September 2009) while the lowest unemployment rate was 2.3% (December 2009).
 
Range of unemployment rate in 2009 = (3.3 – 2.3)%-Point = 1.0%-Point
 
For 2010, the highest unemployment rate was 2.3% (March 2010) while the lowest unemployment rate was 2.1% (September 2010).
 
Range of unemployment rate in 2010 = (2.3 – 2.1)%-Point = 0.2%-Point
 
Hence, we can see that the range of the overall unemployment rate was markedly wider in 2009 than in 2010.
 
Overall Unemployment Rate (Seasonally Adjusted)   
     
Note: The seasonally adjusted unemployment figures are subject to annual revisions when the latest set of seasonal factors is updated, taking into account observations for the latest available year. The most up-to-date data can be accessed here.