How to Calculate Coefficient of Skewness in Excel

Coefficient of skewness is a very important tool to understand a datasetâ€™s main notion. In which direction is the dataset actually lean in which may lead to various fruitful predictions and insights. In this article, we will discuss 3 suitable methods to calculate the coefficient of skewness in Excel in a detailed manner.

Coefficient of Skewness Overview

Skewness represents the degree of asymmetry in a given set of data. In a distribution, when the tail on the left side is longer, you may say that the distribution is negatively skew (left-skew). In this case Mean < Median < Mode. On the contrary, a distribution will be positively skew (right-skew) if the tail on the right side is longer than on the left side.

There are multiple methods of calculating the Skewness coefficient. In this case, Mean > Median > Mode

Among them are Pearsonâ€™s skewness coefficient and General skewness coefficient are notable one.

Pearsonâ€™s Skewness Coefficient

There are two different formats of Pearsonâ€™s skewness coefficient,

• Using mode alongside the mean and standard deviation of the dataset.

The general expression of this formulation is,

Where,

• Sk1 = Skewness Coefficient Value.
• XÂ = Mean of the dataset
• Mo = Mode of the dataset
• S = Standard Deviation
• Using median with the mean and standard deviation of the dataset.

The general expression of this formulation is,

Where,

• Sk1 = Skewness Coefficient Value.
• XÂ = Mean of the dataset
• Md = Median of the dataset
• S = Standard Deviation of the dataset

Apart from Pearsonâ€™s skewness coefficient formula, which is in the SKEW function and in the data analysis toolpak. The general expression of that formula is,

Where Coefficient of Skewness is Ineffective

• Engaging with data that isn’t normally distributed.
• When working with smaller data sets, one should avoid using SKEW because the function can be inaccurate in these circumstances.
• Do not use the SKEW function to calculate the standard deviation of the dataset, as this is not the main purpose of this function.

How to Calculate Coefficient of Skewness in Excel: 3 Easy Methods

Here we are going to use the below dataset for the demonstrate how we can determine various types of coefficient of skewness in excel using various methods. In order to avoid any kinds of compatibility issues, try to use the MS Excel 365 edition.

1. Calculate Pearsonâ€™s Skewness in Excel by Using Descriptive Statistics

Pearsonâ€™s coefficient has been a widely used and accepted skewness coefficient formula. Both two separate variations are described and explained in the following examples.

1.1 Use AVERAGE, MODE.SNGL, STDEV.P Functions

In this method, we are going to use the AVERAGE, MODE.SNGL, STDEV.P functions in order to calculate the coefficient of skewness.

📌Steps:

• Select the cell G4 and enter the following formula:

`=AVERAGE(D5:D15)`

• Pressing enter we got the average of the values in the range of cell D5:D15 in cell G4.

• Select the cell G5 and enter the following formula:

`=MODE.SNGL(D5:D15)`

• Pressing enter we got the Mode of the values mentioned in the range of cell D5:D15 in cell G5.

• Select the cell G6 and enter the following formula:

`=STDEV.P(D5:D15)`

• Pressing enter we got the Standard Deviation of the values mentioned in the range of cell D5:D15 in cell G6.

• Select the cell and enter the following formula:

`=(G4-G5)/G6`

• Pressing enter we got the average of the values mentioned in the range of cells D5:D15 in cell G7.

1.2 Apply AVERAGE, MEDIAN, STDEV.P Functions

In this method, we are going to use the AVERAGE, MEDIAN.SNGL, STDEV.P functions in order to calculate the coefficient of skewness. The primary difference between the previous method and this one is we are going to use the Median instead of the Mode in the previous method.

📌Steps:

• Select the cell G4 and enter the following formula:

`=AVERAGE(D5:D15)`

• Pressing enter we got the average of the values mentioned in the range of cell D5:D15 in cell G4.

• Select the cell G5 and enter the following formula:

`=MEDIAN(D5:D15)`

• Pressing enter we got the Median of the values mentioned in the range of cell D5:D15 in cell G5.

• Select the cell G6 and enter the following formula:

`=STDEV.P(D5:D15)`

• Pressing enter we get the Standard Deviation of the values in the range of cell D5:D15 in cell G6.

• Select the cell G7 and enter the following formula:

`=3*((G4-G5)/G6)`

• Pressing enter we got the Skewness of Coefficient of the values in the range of cell D5:D15 in cell G7.

2. Insert Excel SKEW Function to Estimate Skewness Coefficient

In addition, you can apply the SKEW function to find the skewness of the Maths Score.

📌Steps:

• Below are the data of students with their id and their scores in Math.
• In the cell G5, we need to estimate the skewness of this dataset,

• For this, select cell G5 and enter the following formula and press Enter:

`=SKEW(D5:D15)`

• After pressing Enter, you will notice that the coefficient of skewness of the range of cells D5:D15 is now showing at cell F5.

Read More: How to Calculate Kurtosis in Excel

3. Apply Data Analysis Toolpak to Get Coefficient of Skewness

To calculate the coefficient of skewness using the Data Analysis feature please do the following steps.

📌Steps:

• We have the student’s marks with their id information in the below dataset.
• The coefficient of skewness of those marks needs to be determined.

• First, enable the Data Analysis feature if you donâ€™t find it in the Data tab.
• Then, click on the added Data Analysis feature from Data > Analyze.

• A new window will open, and from there select Descriptive Statistics.
• Click OK after this.

• In the next window. Select cell D4:D15 in the Input Range range box.
• Then select Columns in the Grouped By option.
• Tick the Labels in first row check box.
• After that, set the Output Range as the F4.
• Furthermore, check both the Summary Statistics and Confidence Level for Mean box.

• After that, click OK.
• Lastly, after clicking OK. you will notice that the Skewness Coefficient value is now present in cell G13.

Conclusion

I hope all of these simple methods mentioned above will now help you to apply them in your Excel spreadsheets when you have to calculate the coefficient of skewness. Additionally, for this problem, a workbook is available to download where you can practice these methods. Feel free to ask any questions or feedback through the comment section.

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Rubayed Razib Suprov

Rubayed Razib, holding a BSC degree in Naval Architecture & Engineering from Bangladesh University of Engineering and Technology, serves as a devoted member of the ExcelDemy project. He has contributed significantly by authoring numerous articles and showcasing proficiency in VBA. Razib efficiently automates Excel challenges using VBA macros and actively participates in the ExcelDemy forum, providing valuable solutions for user interface challenges. Apart from creating Excel tutorials, he is interested in Data Analysis with MS Excel,... Read Full Bio

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