Create Box Whisker Plot in Excel

Introduction to Box Whisker Plots

Box whisker plots, also known as box plots, are a graphical representation used to display the distribution of a set of data. They are particularly useful for comparing the distribution of multiple datasets. A box whisker plot displays the five-number summary: the minimum value, the first quartile (Q1), the median, the third quartile (Q3), and the maximum value. In this post, we will learn how to create a box whisker plot in Excel.

Understanding the Components of a Box Whisker Plot

Before creating a box whisker plot, it’s essential to understand its components: - Minimum Value: The smallest value in the dataset. - First Quartile (Q1): The median of the lower half of the dataset, representing 25% of the data. - Median (Q2): The middle value of the dataset, representing 50% of the data. - Third Quartile (Q3): The median of the upper half of the dataset, representing 75% of the data. - Maximum Value: The largest value in the dataset. - Interquartile Range (IQR): The difference between Q3 and Q1, which represents the spread of the middle 50% of the data. - Whiskers: Lines extending from the edges of the box to show the range of the data, excluding outliers.

Creating a Box Whisker Plot in Excel

To create a box whisker plot in Excel, follow these steps: 1. Prepare Your Data: Ensure your data is organized in a column. 2. Go to the “Data” Tab: Click on the “Data” tab in the ribbon. 3. Select “From Current Selection” or “From Table/Range”: Since Excel doesn’t have a direct option to create a box plot, we’ll use the “Histogram” tool as a workaround for Excel versions prior to 2016. For Excel 2016 and later, you can directly create a box plot. 4. For Excel 2016 and Later: - Select your data. - Go to the “Insert” tab. - Click on “Insert Statistic Chart” and select “Box and Whisker”. - Customize your chart as needed.

1. For Earlier Versions of Excel:

   • Select your data.
   • Go to the “Data” tab.
   • Click on “Data Analysis” in the “Analysis” group.
   • Select “Histogram” and click “OK”.
   • In the “Histogram” dialog, select your data range and choose a bin range. You can also select to chart the cumulative percentage.
   • Click “OK”.

2. Manipulating the Histogram to Resemble a Box Plot:

   • After creating the histogram, you’ll need to manually adjust it to resemble a box plot by calculating and plotting the median, Q1, Q3, and the whiskers.
   • Calculate the median, Q1, Q3, minimum, and maximum values using the respective Excel functions (e.g., MEDIAN, QUARTILE, MIN, MAX).
   • Plot these points on the histogram, and use lines to connect them, forming the box and whiskers.

Calculating Key Values for the Box Plot

To manually create or adjust your box plot, you’ll need to calculate several key values: - Median: Use the MEDIAN function, e.g., =MEDIAN(A1:A100). - First Quartile (Q1): Use the QUARTILE function with 1 as the second argument, e.g., =QUARTILE(A1:A100,1). - Third Quartile (Q3): Use the QUARTILE function with 3 as the second argument, e.g., =QUARTILE(A1:A100,3). - Interquartile Range (IQR): Calculate Q3 - Q1. - Minimum and Maximum: Use the MIN and MAX functions, e.g., =MIN(A1:A100) and =MAX(A1:A100).

Interpreting a Box Whisker Plot

Interpreting a box whisker plot involves understanding the distribution of the data: - Symmetry: If the median is in the center of the box, the data is symmetric. If it’s closer to one end, the data is skewed. - Outliers: Points beyond 1.5*IQR from Q1 or Q3 are considered outliers, indicating unusual data points. - Comparing Distributions: Box plots are useful for comparing the distribution of different datasets side by side.

📝 Note: For versions of Excel prior to 2016, creating a true box plot requires more manual effort, including calculating key statistics and using Excel's drawing tools to construct the box and whiskers.

Conclusion Summary

Creating a box whisker plot in Excel can be straightforward for those with Excel 2016 or later, but it requires some workaround for earlier versions. Understanding the components of a box plot and how to calculate key values is essential for both creating and interpreting these plots. By following the steps outlined and practicing with your data, you can effectively use box whisker plots to visualize and compare distributions in Excel.