Five Number Summary and Boxplots

If the distribution is skewed the mean, median and mode are really not very informative. it’s more informative to also provide quartiles also.

Five – number Summary –¬†The five number summary of a distribution consists of the Median, the quatiles¬†Q1 and Q3, and the smallest and largest observations written in the order of Minimum, Q1, Median, Q3 and Maximum.

Boxplots are a popular way of visualizing a distribution, specifically five number summary. A Boxplot incorporates the five number summary as follows.

  • The ends of the box are at the quartiles
  • The median is marked by a line within the box
  • Two lines outside the box extend the smallest and largest observations.

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