Symmetric datasets give us normal distribution curves, whereas asymmetric datasets give us skewed normal curves with different shapes of peaks. Asymmetric curves have non-zero skewness and kurtosis. In this article, we will show you how to create a graph of skewness and kurtosis in Excel effectively with appropriate illustrations.
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Introduction to Skewness and Kurtosis
Skewness is a measure of the level of asymmetry in the distribution of a dataset. When a dataset is not distributed symmetrically, skewness is observed in the normal curve. An asymmetric normal curve can be positively or negatively skewed.
Kurtosis is the measure of tailedness in a normal distribution curve. It can help us find the outliers in a dataset. Based on the shape of the peak and tail, it can be platykurtic, mesokurtic, or leptokurtic.
4 Easy Steps to Create Graph of Skewness and Kurtosis in Excel
In this article, we will demonstrate four easy steps to create a graph of skewness and kurtosis in Excel. We will use the following dataset for this purpose. The dataset contains a Student Name column and a Test Score column.
Step 1: Create Summary Statistics Table
In the first step, we need to create a Summary Table that contains Mean, Standard Deviation, Skewness, and Kurtosis.
- First of all, from your Data tab, go to,
Data → Analysis → Data Analysis
- The Data Analysis pop-up box will appear. Select Descriptive Statistics from there.
- Then click OK to open the Descriptive Statistics dialogue box.
- In the box, select the Input range (Test Score) from cells C5 through C20.
- Next, select the Columns and the Output Range.
- In the Output Range, select the cell where you want your Summary Statistics table to appear.
- Then check the box of Summary Statistics and click OK.
- Hence, the Summary Statistics table will appear in your desired cell.
Step 2: Calculate Bin Intervals
Now we will calculate bin intervals using the Mean and the Standard Deviation values.
- First, insert a column named Intervals.
- Next, select cell F5 and write down the following formula.
- Similarly, type formulas to cells F6 to F9 and determine Bin Intervals. All the formulas are given in the Formula column.
Step 3: Determine Frequency
In this step, we will determine Frequency using the Histogram tool.
- First, go to Data >> Data Analysis.
- Then, select Histogram. A new dialogue box will pop up.
- In the box, select cells C5 through C20 as the Input Range.
- Then choose cells F5 to F9 as the Bin Range.
- Next, select Output Range to show Frequency in a specific cell and click OK.
- Consequently, you will get the Frequency for the Bin Intervals.
Step 4: Plot a Graph of Skewness and Kurtosis
Finally, it’s time to plot the graph of skewness and kurtosis. We will use the Charts tool for this purpose.
- Firstly, select the data of Bin Intervals and Frequency.
- Next, go to Insert >> Scatter and then select Scatter with Smooth Lines.
- Finally, you will have your graph of skewness and kurtosis.
- If you want to format the chart title, axis title, gridlines others, you can do this by using the Chart Design feature.
Thanks for making it this far. I hope you find this article useful. Now you know how to create a graph of skewness and kurtosis in Excel. Please let us know if you have any further queries and feel free to give us any recommendations in the comment section below.