Introducing Spearman’s Coefficient

  • This task introduces Spearman’s coefficient of ranked correlation, as a tool to solve the problem of making quantitative comparisons between pairs of rankings. Students are presented with a list of the ’10 best jokes’ from the Edinburgh Fringe (as voted for by a set of 2000 viewers of the Dave TV channel.)
  • Students make their own ranked list of the jokes, and compare this to the published results – first informally, and then by calculating Spearman’s coefficient.

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Strand

Statistics

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Prior Knowledge

Students will not need any specific prior knowledge beyond the informal ideas of correlation that should be familiar from GCSE mathematics.

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Relevance to Core Maths Qualifications

  • AQA
  • C&G
  • Eduqas
  • Pearson/ Edexcel
  • OCR

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Suggested Approaches

Work through the PowerPoint presentation supplied, using the notes provided to lead whole-class and individual questioning and discussion. The activities in this task are suitable for a variety of approaches, including individual work, paired work, and whole class discussion.

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Resources/Documentation

The supplied PowerPoint presentation includes extensive notes that address the key teaching points for an introductory lesson on this topic. 

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Relevant Digital Technologies

Students could use spreadsheets to perform the required calculations; however it is important to make sense of the formula and calculate some cases ‘by hand’.

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Possible Extensions

  • The work presented here could be extended to include determination of ranks from raw data, and dealing with the case of tied ranks.
  • You may wish to present simple (sketched) scatter diagrams to provide a visual image for the different types and values of correlation in the lesson.