Correlation

Correlation charts are often associated with causality and they should be used with caution.

Correlation can show:

  • increases with
  • relates to
  • changes with
  • varies with
  • caused by

Anscombe’s Quartet

Anscombe’s quartet is a powerful illustration of the drawback of relying solely on basic descriptive statistics to summarise data. The data in all 4 of the graphs in the quartet are virtually identical when using standard descriptive methods. Looking at your data before analysing it is something that Anscombe was passionate about.