How To Read A Boxplot

box plot statistics Jun 13, 2023

It's Tech Tip Tuesday!

Today, I want to shed light on a powerful visualization tool that is often overlooked but holds tremendous value in data analysis: the boxplot. 📈

Boxplots are a fantastic way to summarize and interpret data, providing valuable insights into the distribution, central tendency, and variability of a dataset. By understanding how to read them effectively, you can unlock a wealth of information hidden within your data. Let's dive in! 💡

📌 Step 1: Understand the Anatomy of a Boxplot

• The box represents the interquartile range (IQR), encapsulating the central 50% of the data.
• A vertical line inside the box marks the second quartile or the median, showcasing the dataset's central tendency.
• Whiskers extend from the box, indicating the range of the data, excluding outliers.
• Outliers, represented as individual points, lie outside the whiskers and may signify noteworthy data points.

📌 Step 2: Interpret the Boxplot

• Skewness: Observe the box's position relative to the median. If it is closer to one whisker, the data may be skewed in that direction.
• Spread: The length of the whiskers suggests the variability of the data. Longer whiskers indicate greater dispersion, while shorter ones indicate less variability.
• Outliers: Identify any individual points lying outside the whiskers. These may indicate extreme values or potential anomalies requiring further investigation.

📌 Step 3: Bonus Tips

• Compare boxplots side by side to understand differences in distributions across various groups or categories.
• Use boxplots to identify trends, seasonality, or changes in distribution over time.
• Boxplots are most valuable with > 15 data points. (I've seen boxplots done on 5 data points!...NOT GOOD!)

Remember, a picture is worth a thousand words, and a boxplot has a wealth of knowledge!

Let's spread the knowledge and remember:
Friends don't let friends read boxplots incorrectly!