Interquartile Range

Box-and-whisker plots are helpful in interpreting the distribution of data. From looking at a box and whisker plot, you can tell the median, and range very quickly.

It is useful to see data displayed graphically.   One way to do this is use the box and whisker plot.   A box and whisker plot is a diagram that summarizes data using the median, the upper and lower quartiles, and the extreme values (minimum and maximum).   Box and whisker plots are also known as box plots.

Remember they are constructed using a five-number summary of the data:

  1. Minimum
  2. Q1 (lower quartile)
  3. Q2 (median)
  4. Q3 (upper quartile)
  5. Maximum

The interquartile range (IQR) is the difference between the first and third quartiles.