Box plot: Difference between revisions

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role of the whisker
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* the smallest value that is ''not'' an outlier is 5
* the data is [[skewness|skewed]] to the left (''negatively skewed'')
 
The horizontal lines (the "whiskers") extend to at most 1.5 times the box width
(the [[interquartile range]]) from the ends of the box. They must end
at an observed value, thus connecting all the values outside the box
that are not more than 1.5 times the box width away from the box.
 
There are alternative implementations of this detail of the box plot
for various software packages, such as the whiskers extending to at most the
5th and 95th (or some more extreme) percentiles. Not only do they not conform to
[[Tukey's|John Tukey]] original definition. They also tend to produce
"outliers" for all data sets larger than ten, no matter what the shape
of the distribution.