If the data do not extend to the end of the whiskers, then the whiskers extend to the minimum and maximum data values. If there are values that fall above or below the end of the whiskers, they are plotted as dots. The whiskers represent the expected variation of the data. The whiskers extend 1.5 times the IQR from the top and bottom of the box. The lines that extend from the box are called whiskers.The length of the box is the difference between these two percentiles and is called the interquartile range (IQR). These two quantiles are also called quartiles because each cuts off a quarter (25%) of the data. The bottom and top of the box show the 25 th and 75 th quantiles, or percentiles.If the data are skewed, the median will be closer to the top or to the bottom of the box. If the data are symmetrical, the median will be in the center of the box. Half of the data is above this value, and half is below. The center line in the box shows the median for the data.See the 'Comparing outlier and quantile box plots' section below for another type of box plot.
The term “box plot” refers to an outlier box plot this plot is also called a box-and-whisker plot or a Tukey box plot.
