How To Draw Normal Distribution Curve In Excel

A bell curve (also known equally normal distribution curve) is a way to plot and analyze data that looks similar a bong curve.

In the bong bend, the highest point is the ane that has the highest probability of occurring, and the probability of occurrences goes down on either side of the bend.

It is often used during employee performance appraisals or during evaluation in exams (ever heard – "You will be graded on the bend?").

Now before I jump in on how to create a bell curve in Excel, let's get a ameliorate understanding of the concept by taking an example.

Understanding the Bell Bend

Suppose you work in a team of 100 members and your manager tells you that your operation volition be relative to others and will be evaluated on the bell curve.

This ways that fifty-fifty if your team is the best team ever and y'all're all superheroes, only a handful of you would get the acme rating, almost of the people in your squad would get an average rating, and a handful volition get the lowest rating.

Prototype Source: EmpxTrack

Merely why practise nosotros need the bell curve?

Fair question!

Suppose you accept a class of 100 students that announced for an examination. According to your grading system, anyone who gets to a higher place lxxx out of 100 gets an A grade. But since you set a really piece of cake paper, everyone scored above 80 and got the A grade.

At present at that place is cipher wrong in this kind of grading arrangement. Nevertheless, using it, you can not differentiate between someone who got 81 and someone who got 95 (every bit both would become the A grade).

To keep the comparison fair and keep the competitive spirit alive, a bell curve is often used to evaluate performances (at least that's how it was when I was in college).

Using the bell bend approach, the marks of students are converted into percentiles that are then compared with each other.

Students getting higher marks are on the correct side of the curve and students getting depression marks are on the left of the curve (with about of the students being in the heart around mean score).

Now to understand bell curve, you need to know about 2 metrics:

• Mean – the average value of all the data points
• Standard Deviation – it shows how much the dataset deviates from the mean of the dataset. For example, suppose you have a group of fifty people, and y'all are recording their weight (in kgs). In this dataset, the average weight is lx kg, and the standard divergence is 4 kg. Information technology means that 68% of the people's weight is within one standard divergence from the mean – which would be 56-64 kg. Similarly, 95% of the people are within 2 standard deviation – which would be 52-68 Kgs.

When you lot have a dataset that is normally distributed, your bell bend will follow the below rules:

•  The middle of the bong bend is the mean of the data point (also the highest indicate in the bell curve).
• 68.2% of the total data points prevarication in the range (Hateful – Standard Deviation to Mean + Standard Divergence).
• 95.5% of the full data points prevarication in the range (Mean – 2*Standard Deviation to Hateful + 2*Standard Deviation)
• 99.7% of the full data points prevarication in the range (Mean – three*Standard Departure to Mean + 3*Standard Deviation)

Image Source: MIT News

Now allow's see how to create a bong curve in Excel.

Creating a Bong Curve in Excel

Let'south have an example of a course of students that accept been scored in an exam.

The hateful score of the course is 65 and the standard deviation is 10. (You can calculate the mean using the AVERAGE function in Excel and Standard Divergence using the STDEV.P function).

Here are the steps to create a bell curve for this dataset:

This will give you a bell curve in Excel.

Now you tin can alter the chart championship and adjust the centrality if you lot need.

Note that when you lot have a depression standard departure, you get a packed slim bong curve, and when yous have a loftier standard departure, the bell curve is wide and covers more expanse on the chart.

This kind of bell curve can be used to place where a data point lies in the nautical chart. For example, in instance a squad is full of high performers, when evaluated on a curve, despite beingness a high performer, someone can go an average rating as he/she was in the eye of the curve.

Note: In this blog mail, I have discussed the concept of a bell curve and how to create it in Excel. A statistician would exist meliorate suited to talk almost the efficacy of the bell curve and limitations associated with information technology. I am more of an Excel guy and my involvement with Bell curve has been limited to the calculations I did when I worked every bit a Fiscal Analyst.

Hope you lot found this tutorial useful!

Permit me know your thoughts in the comments section.

You May Besides like the following Excel Tutorials:

• How to Make a Histogram in Excel.
• How to Calculate Compound Interest in Excel + Costless Calculator.
• How to Create a Heat Map in Excel.
• Stride Chart in Excel.
• How to Create a Timeline / Milestone Nautical chart in Excel.
• Creating a Pareto Chart in Excel.
• Creating a Pie Chart in Excel
• Advanced Excel Charts
• How to Find Slope in Excel? Using Formula and Chart
• Calculate Area Under Curve in an Excel

Source: https://trumpexcel.com/bell-curve/

Posted by: greenlyharsecy.blogspot.com

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