A Box & Whisker Plot
By: DIonna Hudson
What is a box and whisker plot?
A box and whisker plot is a graphic representation of a distribution by a rectangle, the ends of which mark the maximum and minimum values, and in which the median and first and third quartiles are marked by lines parallel to the ends
What is the purpose of a box and whisker plot?
A box and whisker plots purpose is to graph a set of numercal data. A box-and-whisker plot shows the distribution of a set of data along a number line, dividing the data into four parts using the median and quartiles.
What are examples of a situation where box and whisker plots are used?
You can use a box and whisker plots when you have multiple data sets from independent sources that are related to each other in some way. An example of a situation in which you could use in a box and whisker plot would be your test scores, the ages of your family members, or the difference in the temperature over a period of time.
What are the advantages of using a box and whisker plot?
The advantages of using a box and whisker plot are that when it is put together it is not cluttered and the graph highlights the important information about the data. And it also provides a summary of a large set of data. Also a box and whisker plot is one of the few graphs that shows outliers. An outlier is a result that falls outside of the rest of the data.
What are the disadvantages of using a box and whisker plot?
One issue with handling such large amounts of data in a box plot is that the exact values and details of the distribution of results are not retained. A box plot shows only a simple summary of the distribution of results, so that it can be quickly viewed and compared with other data.
How do you make a box and whisker plot?
Visit the site http://www.purplemath.com/modules/boxwhisk.htm to get an in depth view of how to make a box and whisker plot.
Are there different variations of a box and whisker plot?
There are 2 types of variations: Variable width box plots illustrate the size of each group whose data is being plotted by making the width of the box proportional to the size of the group. A popular convention is to make the box width proportional to the square root of the size of the group. Notched box plots apply a "notch" or narrowing of the box around the median. Notches are useful in offering a rough guide to significance of difference of medians; if the notches of two boxes do not overlap, this offers evidence of a statistically significant difference between the medians. The width of the notches is proportional to the interquartile range of the sample and inversely proportional to the square root of the size of the sampleThese two variation are basically the same