created by: Jennifer Nord,
A box-and-whisker plot can be useful for handling many data values. They allow people to explore data and to draw informal conclusions when two or more variables are present. It shows only certain statistics rather than all the data. Five-number summary is another name for the visual representations of the box-and-whisker plot. The five-number summary consists of the median, the quartiles, and the smallest and greatest values in the distribution. Immediate visuals of a box-and-whisker plot are the center, the spread, and the overall range of distribution.
The first step in constructing a box-and-whisker plot is to first find the median, the lower quartile and the upper quartile of a given set of data. Example: The following set of numbers are the amount of marbles fifteen different boys own (they are arranged from least to greatest).
(*If you're finding the median in an ordered set with an even number of values, you must take the average of the two middle numbers. For example: 3, 5, 7, and 10. Add the two middle numbers. 5 + 7 = 12. Divided 12 by 2 to get the average. 12 / 2 = 6. Therefore 6 is the median for the ordered set of 3, 5, 7, and 10.)
Now we begin to draw our graph.
Last update: December 10, 1995.
Jennifer Nord's homepage: Jennifer Nord's little nitch in the woods
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