Watch the animation for calculating range and then consider the question below.

Why use these techniques? Is it appropriate?

  • The range is used to show the spread of a data set.
  • By calculating the range of two or more different sets of data, it allows us to compare the range easily e.g. temperature data for different locations.
  • By calculating the range and the mean, it shows how well the mean value represents the set of data. If the range is a high number – or there is a large spread, then this may be an indication that calculating the mean would not be representative of the set of data and another central tendency technique would be more appropriate e.g. mode or median.

Evaluate the strengths and limitations of calculating the range.

Strengths
Limitations

Strengths of calculating the range:

  • The range is a very easy calculation.
  • Takes into consideration any anomalies (high or low values) in the set of data.

Weaknesses of using the range:

  • A large amount of the data is ignored as only the maximum and minimum values are used.
  • Anomalies can mean that the range value is not representative of the data set.