31 lines
1.7 KiB
Markdown
31 lines
1.7 KiB
Markdown
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---
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title: Reading Box Plots
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---
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## Reading Box Plots
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Box Plots might seem unintuitive at first glance, but they are a great way to convey a lot of information of a compact format. Here's how you can read the informations contained in a
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Box Plot:
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The Box Plot has several elements that we can recognize:
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* The box, which is bisected in two parts
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* Two whiskers, above and below the box
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* Possibly some scattered points: the outliers
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Each section of the box plot represents the interval of a quartile of the population of data. What this means, is that 25% of the data lies within the two ends of the lower whisker, 25% within the interval spanned by the bottom of the box and the median line, 25% within the median and the top of the box, and 25% in the upper whisker. Any statistical outlier is represented as a point outside of the box.
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In the example reported above we would have (using approximate numerical values):
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* a quarter of the data between 1 and 3 (lower whisker)
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* a quarter of the data between 3 and 5 (lower part of the box)
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* a quarter of the data between 5 and 7.5 (upper part of the box)
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* a quarter of the data between 7.5 and 10 (upper whisker)
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* two outlier points above the boxplot
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Notice that the line that bisects the box represents the **Median** (50th percentile) and **not the Mean**.
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#### More Information:
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For more informations:
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* <a href='https://en.wikipedia.org/wiki/Box_plot' target='_blank' rel='nofollow'>Wikipedia: Box Plot</a>
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* <a href='https://www.khanacademy.org/math/probability/data-distributions-a1/box--whisker-plots-a1/v/interpreting-box-plots' target='_blank' rel='nofollow'>Khan Academy: reading Box Plots(video)</a>
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