Is the median always in the exact middle of a boxplot?

1 Answer
Jul 1, 2015

Not necessarily: the band inside the box will always be the median, but it may or may not fall exactly within the middle of the box.

Explanation:

While the median is that thick line within the box. The box in a box plot shows you the interquartile range , meaning data falling between the first and third quartile. If the data is skewed, the median will not be exactly in the middle of the IQR.

http://www.physics.csbsju.edu/stats/box2.html

Check out this example in the image below:
Wikipedia

The medians can be found throughout the boxes because of how each set of data is distributed. Outliers will make a difference.

Check out this good resource on how to read a box and whiskers plot (also known as a box plot).