Box plot  From Wikipedia, the free encyclopedia Jump to:
navigation, search Figure 1. Box plot of data from the
Michelson–Morley experiment  In descriptive statistics, a box
plot or boxplot is a convenient way of graphically depicting
groups of numerical data through their quartiles. Box plots may
also have lines extending vertically from the boxes (whiskers)
indicating variability outside the upper and lower quartiles,
hence the terms box-and-whisker plot and box-and-whisker
diagram. Outliers may be plotted as individual points. Box plots
are non-parametric: they display variation in samples of a
statistical population without making any assumptions of the
underlying statistical distribution. The spacings between the
different parts of the box indicate the degree of dispersion
(spread) and skewness in the data, and show outliers. In
addition to the points themselves, they allow one to visually
estimate various L-estimators, notably the interquartile range,
midhinge, range, mid-range, and trimean. Boxplots ca