## How to find an interquartile range on a boxplot

Finding an interquartile range on a boxplot is easy! (If you only have numbers, see How to  find an interquartile range from a set of numbers). This how-to will show you how to find an interquartile range in a couple of easy steps.

Let’s find the interquartile range for the above graph.

• Step 1: Find Q1.Q1 is represented on a boxplot by the left hand edge of the “box”.

In the above graph, Q1 is approximately 2.5. (If you are interested, a better explanation of what Q1 is can be found in this article on finding the five number summary.)

• Step 2: Find Q3.
Q3 is represented on a boxplot by the right hand edge of the “box”.

Q3 is approximately 12 in this graph.
• Step 3: Subtract the number you found in step 1 from the number you found in step 3.
This will give you the interquartile range. 12 – 2.5 = 9.5.
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## 11 Responses to “How to find an interquartile range on a boxplot”

1. ### How to find an interquartile range in statistics « How to Do Everything Statistics said:

Aug 22, 09 at 8:40 am

[...] An interquartile range–the different between the biggest and smallest values in the middle fifty percent of data–can be a tricky concept to grasp at first. However, this article breaks it down into a couple of easy steps, so you’ll have the answer in no time! (If you have a boxplot, see this article to find the interquartile range). [...]

2. ### Christine Mao said:

Sep 12, 09 at 7:07 pm

This article was simple to comphrehend. The diagram and the steps explain everything you would need to know. I was able to understand more of the interquartile range on a boxplot. The book helped, but the article was more helpful.

3. ### Lisa Barcomb said:

Oct 25, 09 at 6:25 pm

I understood this article it was easy because of the diagram, its nice when you have the diagrams to look at and see what you are doing. But the interquartile range is alittle difficult by plotting it on the boxplot.

4. ### Vanessa DuBarry said:

Dec 14, 09 at 9:43 pm

Very easy to learn this. Thanks for this blog!, its just way easier than the book explains it.

5. ### crystal lydick said:

May 04, 10 at 10:18 am

Our book does not seem to explain innterequartile range as easily to me as our practically cheating book has. I do not understand our book as I do the practically cheating book.

6. ### SeaTab said:

Apr 11, 11 at 6:40 pm

Thank you great site!

7. ### Statistics How To» Blog Archive » How to find an interquartile range on a boxplot « Gregory Reese Research said:

Sep 03, 11 at 1:51 pm

8. ### How to find an Interquartile Range in Statistics I | said:

Apr 20, 12 at 10:59 am

[...] or if you want to check your work, check out the interquartile range calculator. If you have a boxplot, see this article to find the interquartile range. Feel like Cheating at Statistics? This is the Statistics Handbook that your professor doesn't want [...]

9. ### weultras.com said:

May 04, 12 at 6:35 am

weultras.com…

[...]How to find an interquartile range on a boxplot |[...]…

10. ### gertrude said:

Feb 21, 13 at 3:23 pm

this is soo perfect i love this website!

11. ### What is a Five Number Summary? | said:

Mar 02, 13 at 11:54 pm

[...] five number summary can be represented by a boxplot, which is comprised of a box and “whiskers”, or lines on the left and the right of the [...]