What do the whiskers on a box plot mean?
A Box and Whisker Plot (or Box Plot) is a convenient way of visually displaying the data distribution through their quartiles. The lines extending parallel from the boxes are known as the “whiskers”, which are used to indicate variability outside the upper and lower quartiles.
What are the tails on a box plot?
The Boxplot as an Indicator of Tail Length The tails are the extremities of the sample or population, rather than the centre. Lack of symmetry entails one tail being longer than the other.
How do you find the whiskers in a Boxplot?
The box in the box plot will show the median and the first and third quartiles. The length of the upper whisker is the largest value that is no greater than the third quartile plus 1.5 times the interquartile range. In this case, the third quartile plus 1.5 times IQR is 10 + 1.5*6 = 19.
Where do the whiskers end on a box plot?
The “whiskers” extend from the ends of the box to the smallest and largest data values. The median or second quartile can be between the first and third quartiles, or it can be one, or the other, or both. The box plot gives a good, quick picture of the data.
Does a box and whisker plot show standard deviation?
In addition to showing median, first and third quartile and maximum and minimum values, the Box and Whisker chart is also used to depict Mean, Standard Deviation, Mean Deviation and Quartile Deviation.
What do the whiskers tell you about the two data sets?
The whiskers: The lines coming out from each box extend from the maximum to the minimum values of each set. Together with the box, the whiskers show how big a range there is between those two extremes. Larger ranges indicate wider distribution, that is, more scattered data. Taller boxes imply more variable data.
Can a box and whisker plot have only one whisker?
For a box-and-whisker plot you order the data numerically from smallest to largest and find the lower quartile, median and upper quartile. The median is 2, the lower quartile (the median of the values less than the median) is 1 and the upper quartile is 3. Thus the box extends from 1 to 3 are there are no whiskers.
How do box and whisker plots work?
A box and whisker plot—also called a box plot—displays the five-number summary of a set of data. The five-number summary is the minimum, first quartile, median, third quartile, and maximum. In a box plot, we draw a box from the first quartile to the third quartile. A vertical line goes through the box at the median.
How to create a boxplot using Stata graph box?
If you are trying to create a relatively standard boxplot, you probably want to use Stata’s graph box command, however, if you wish to create a boxplot with a non-standard attribute (e.g. a boxplot that includes a marker at the mean), you can do this using Stata’s graph twoway commands.
What does a box and whisker plot look like?
In this case, the box plot looks as if it is shifted to the left with a long right whisker and a short right whisker. Lastly, if most of the data points are small and few are very large compared to the smaller values, the distribution is left-skewed (Mean > Median).
How to change the color of the graph in Stata?
Lastly, we can change the actual color of the box plot by using the box (variable #, color (color_choice)) command: graph box mpg, box (1, color (green)) A full list of available colors can be found in the Stata Documentation.
What can a box plot be used for?
A box plot is a type of plot that we can use to visualize the five number summary of a dataset, which includes: This tutorial explains how to create and modify box plots in Stata.