Box-Plot (Simply explained and create online)

In this tutorial you will learn what a boxplot is, what information can be read in a boxplot and then we will look at what we have learned with an example.

Boxplots are used in statistics to graphically display different parameters at a glance. This is why boxplots are so difficult to understand at the beginning, because a lot of information about the data is provided in one diagram. Among other things, the median, the interquartile range and the outliers can be read in a boxplot.

The data used must have metric scale level. Such as a person's age, annual household electricity consumption, or temperature.

What is the interpretation in a boxplot?
The box itself indicates the range in which the middle 50% of all values lie. Thus, the lower end of the box is the 1st quartile and the upper end is the 3rd quartile. Therefore below q1 lie 25% of the data and above q3 lie 25% of the data, in the box itself lie 50% of your data.

In the boxplot, the solid line indicates the median and the dashed line indicates the mean.

For example, if the median is 34, that means that half of the participants are younger than 34 and the other half are older than 34. The median thus divides the people into two equal groups.

The T-shaped whiskers in the boxplot go to the last point, which is still within 1.5 times the interquartile range. What does it mean? The T-shaped whisker is either the maximum value of your data but at most 1.5 times the interquartile range. Therefore, if you have an outlier, then the whisker goes up to 1.5 times the interquartile range. If there is no outlier, the whisker is the maximum value.

So the upper whisker is either the maximum value or 1.5 times the interquartile range. Depending on which value is smaller. Exactly the same applies to the lower whisker in the boxplot, which is either the minimum or 1.5 times the interquartile range.

Points that are further away are considered outliers. If no point is further away than 1.5 times the interquartile range, the T-shaped whisker thus gives the maximum or minimum value.

More information on the boxplot:

Create boxplot online:

[memelchang]

As a medical student who has to take statistics in order to graduate, thank you so much. This video is a life saver. I really cannot express in words how grateful I am. A year of classes and I barely grasped the concepts of variables, but two minutes made it all finally make sense

[jiggyfeets]

You are a life saver. I am a computer science student and i've never done anything with data or statistics but I got a competition tomorrow. You're a life saver

[phoenixblack]

Oh my God! Why can’t professors put as easily as you just did? Thank you so much! And thank you for the link to the data calculator!!

[svetlanama]

Thank you. I was confused why the whiskers were not the same length, but now I understand that one can indicate 1.5xIQR, while the other might show min/max value if there are no outliers.

[basquiatttt]

Today is a happy day for me as I finally grasped this, which I thought to be a very hard-to-understand chart. Thanks for the great explanation and tooling!

[simga]

I have applied statistics course in my Master of data science. I have to say that watching 2 videos of you in 16 min made me understand perfectly 3h of lecture at University. Thanks for the Video. Keep it up😊

[mostafamarwanmostafa]

Thank You !! Very short, Informative and Excellent explanation!

[ravitejadevarakonda]

Explained in a very simple and understandable manner 👍🏻

[TochukwuVictor-qexd]

Super helpful. I love your presentation.

[vitaliyshastun]

Thanks! Easy to understand and clear ☀

[qnmimjs]

You are amazing
This was the most valuable explanation that I have ever saw

[MsLaBajo]

So helpful for my stats class! Thank you!

[terran]

Thank you, this was really comprehensible

[srsh]

Thank you for the breakdown. You helped me understand this topic much better.

[LaunchBizNow]

Thank you so much for this great video. I understand a lot better.

[khalidsultani]

Thanks for posting this awesome explanation ❤

[ShohanDominic]

Easy to understand and well explained. Thanks

[Neo-efzi]

Nice explanation ma'am....thank you!

[KingfisherLtd]

Hi. It was a great lesson. What is the minimal number of variables to use a box plot graph? Is it 'the more data the better' rule like in histograms? Best wishes.

[charafdev]

Great video, good explanation! Thanks :)