How to Calculate Skewness in Excel
In this Excel tutorial lesson, you will learn what skewness is and how to calculate skewness in Excel application.
To find the skewness in Excel, please prepare some data tables.
Table of Contents
Calculate Skewness using SKEW function
Excel provides a SKEW function. Syntax is:
=SKEW(number1, [number2], …)
In this example, the formula is: =SKEW(B2:B13)
Skewness here is strongly above 0 (skewness > 0), which means that it is a right-sided asymmetry. The conclusion is that for many months, sales were significantly lower than the average sales.
Calculate Skewness using Data Analysis ToolPak Add-In
First, you need to make sure your Data Analysis Toolpak Add-In is installed. Here is the lesson on how to install Data Analysis Toolpak Add-In.
Go to Ribbon to the Data tab. Click the Data Analysis button.
A new window appears. Choose Descriptive Statistics and click OK.
Enter the proper parameters:
- Input Range – range of your data ($B$1:$B$13 in my example).
- Labels in first row – there are labels in my data table.
- Output Range – choose where you want to get your skewness calculated (I chose the same Sheet $E$1:$F$15).
- Summary statistics – make sure it is checked.
And this is how you see my statistics summary. Skewness is calculated in row 10. The result is the same as in Example 1 where we checked how to calculate Skewness using the SKEW Excel function.
While the formula 3 * (Mean – Median) / Standard Deviation provides an approximation of skewness (Pearson’s coefficient), Excel’s SKEW function offers a more precise calculation. It’s not the same as the sample skewness calculated by the SKEW function or the Data Analysis ToolPak, which use a different formula involving the third moment.
While this formula can provide a rough estimate, the SKEW function is the standard and more accurate method for calculating sample skewness in Excel.
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