**Excel Bell Curve (Table of Contents)**

- Bell Curve in Excel
- How to Make a Bell Curve in Excel?

## Bell Curve in Excel

Bell curve in excel is mostly used in the Employee Performance Appraisal or during Grading of the Exam Evaluation. The Bell curve is also known as the Normal Distribution Curve. The main idea behind the bell curve is when everybody in the team or class is a good performer, how will you identify who is the best performer, who is the average performer and who is the poor performer in the team or class.

Excel functions, formula, charts, formatting creating excel dashboard & others

So before we proceed further, let us first understand the concept of the Bell Curve in Excel with the help of a simple example.

Suppose there are 100 students in a class who appeared for the exam, as per the education system, whoever gets more than 80 will get an A grade. But then there will be no difference between a student who scores 99 and a student who scores 81 as both would get an A grade.

Using the Bell curve approach, we can convert the marks of the students into Percentile and then compare them with each other. Students getting lower marks will be on the left side of the curve, and students getting higher marks will be on the right side of the curve, and most of the students who are average will be in the middle of the curve.

We need to understand two concepts to understand this theory better.

- Mean – It is the average value of all Data Points.
- Standard Deviation – It shows how much Dataset varies from the Mean of the Dataset.

### How to Make a Bell Curve in Excel?

To make a bell curve in Excel is very simple and easy. Let’s understand how to make a bell curve in excel with some examples.

You can download this Bell Curve Excel Template here –Bell Curve Excel Template

#### Example #1

Suppose there are 10 students in a class who has got the below marks out of 100.

You can calculate the Mean with the help of the Average Function.

In cell B12, I have inserted the Average Function, as you can see in the below screenshot.

The result of the Average Function is 86. So we can say that the Mean in our example is 86, which will be the center of the Bell curve.

Now we need to calculate the Standard Deviation, which we can do with the help of the STDEV.P function.

So the result of the standard deviation in our case is 2.58.

In this case, the value of 2.58 means that most of the students will be in the range of 86-2.58 or 86+2.08.

Now to calculate the normal distribution, you need to insert the formula for normal distribution in the next cell of Marks. The syntax of the formula is as below.

So let us insert the formula from cell C2.Please make sure that you freeze the cells for Mean and standard deviation in the formula.

The Result is given below.

Now drag the formula in the below cells till cell C10.

**Insert a Bell Curve in Excel (Normal Distribution Curve)**

Now, as all the data is ready with us for the Bell curve, we can insert a Bell curve chart in excel.

First, select the Marks of all student and the Normal Distribution column, which we calculated above, and under the **Insert** tab, click on **Recommended Charts** as shownbelow.

Now under the Recommended chart, you will see lots of option for different types of charts. But to get a normal distribution curve (Bell Curve), follow the below steps.

- First, click on
**All Charts**.

- Now select
**XY Scatter**Chart Category on the left side.

- You can see the built-in styles at the top of the dialog box; click on the third style,
**Scatter with Smooth Lines.**

- Select the Second chart and click on
**Ok**.

- So now you will be able to see the Bell curve in your excel sheet as below.

Now when you look at the Bell Curve, you can see that the maximum number of student will be in the range of 83.42 & 88.58(86-2.58 =83.42 & 86+2.58 = 88.58).

In our example, there are 6 students who are in between 83 & 88. So I can say that they are the average performers in the class. Only 2 students have scored more than 88,, so they are the best performers in the class. Only one student has scored below 83, so he is a poor performer in the class.

**Remove the Vertical axis from the graph.**

The Horizontal axis is the Marks scored, and the Vertical axis is the Normal Distribution. If you do not want to see the Vertical axis of Normal Distribution, you just need to follow the below steps.

- Click on the graph, and you will see the
**“+”**sign on the right corner of the graph area.

- After clicking on the + sign, you will see an option for Axis as below. Click on the Axis button, and you will see two options for Horizontal Axis and Vertical Axis. Just uncheck the
**Vertical Axis**.

- This Bell curve helps you identify who the top performer in your team is and who is the lowest performer and help you decide the ratings of the employee.

**When Data is not sorted in Ascending Order**

So in the above example, Marks were sorted in ascending order, but what if the data is not arranged in the ascending order. Then we will not be able to get a smooth bell curve as above. So it is very important to arrange the data in ascending order to get a smooth bell curve in excel.

#### Example #2

Let’s take a similar example, but data will not be sorted in ascending order this time.

The Average (which is Mean), Standard Deviation and Normal Distribution will all remain the same.

But the Bell curve graph of the same example will look different because Marks were not sorted in the Ascending order. The Bell curve graph will now look as below.

So as you can see in the graph, it started with 83 and ends with 88. Also, you can notice that the graph is not as smooth as it was in example 1. So to get a smooth Bell curve in excel, it is very important to sort the data in ascending order.

### Things to Remember

- Always make sure to sort the data in Ascending order to get a smooth bell curve in Excel.
- Remember to Freeze the Cell of Average (Mean) & Standard Deviation when inputting the formula for the Normal Distribution.
- There are two formulas for Standard Deviation – STDEV.P & STDEV.S (P stands for Population & S stands for Sample). So when you are working on Sample data, you need to use STDEV.S.

### Recommended Articles

This has been a guide to Bell Curve in Excel. Here we discuss how to make a Bell Curve in Excel along with excel examples and a downloadable excel template. You can also go through our other suggested articles –

- Scatter Chart in Excel
- Scatter Plot Chart in Excel
- Combination Charts in Excel
- Stacked Area Chart

Popular Course in this category

Related Courses

0 Shares

## FAQs

### Why is my bell curve not smooth on Excel? ›

**Always make sure to sort the data in Ascending order to get a smooth bell curve in Excel**. Remember to Freeze the Cell of Average (Mean) & Standard Deviation when inputting the formula for the Normal Distribution. There are two formulas for Standard Deviation – STDEV. P & STDEV.

**Can you create a bell curve in Excel? ›**

**From the histogram, you can create a chart to represent a bell curve**. To create a sample bell curve, follow these steps: Start Excel. These formulas will generate the average (mean) and standard deviation of the original data, respectively.

**How do you make a normal curve in Excel? ›**

To make a normal distribution graph, **go to the “Insert” tab, and in “Charts,” select a “Scatter” chart with smoothed lines and markers**. When we insert the chart, we see that our bell curve or normal distribution graph is created.

**What is the best way to curve? ›**

A simple method for curving grades is to **add the same amount of points to each student's score**. A common method: Find the difference between the highest grade in the class and the highest possible score and add that many points. If the highest percentage grade in the class was 88%, the difference is 12%.

**What is a perfect bell curve? ›**

Perfectly normal bell curves must be symmetrical to be a true bell curve. **The graph must be mirrored or centered around the midpoint and have the same mean, median, and mode**. The mean, median, and mode are equal and have the same value. This is what makes them perfectly normal.

**Why bell curve is outdated? ›**

Some can debate that the bell curve **creates too much emotional stress, and most importantly, it destroys the loyalty factor and leads to high levels of attrition**. A study by the Society for Human Resource Management found that 90% of performance appraisals are painful and don't work.

**How do you make data normally distributed? ›**

- Checking the distribution with Skewness.
- Checking the distribution of some variables using Histogram.
- Checking the distribution of variables using KDE plot.
- Checking the distribution of variables using a Q-Q plot.
- Transformations to change the distribution of features.

**How do you put data under a curve in Excel? ›**

On the worksheet that contains your chart data, in the cells directly next to or below your existing source data for the chart, enter the new data series you want to add. Click the worksheet that contains your chart. **Right-click the chart, and then choose Select Data**.

**How do you draw a standard normal curve? ›**

Begin by drawing a horizontal line (axis). Next, draw a normal (bell-shaped) curve centered on the horizontal axis. Then draw a vertical line from the horizontal axis through the center of the curve, cutting it in half.

**How do I convert non normal data to normal in Excel? ›**

**Box-Cox Transformation** is a type of power transformation to convert non-normal data to normal data by raising the distribution to a power of lambda (λ). The algorithm can automatically decide the lambda (λ) parameter that best transforms the distribution into normal distribution.

### How can I make Excel data smoother? ›

Another way to smooth out data series in Excel is to **use the Lowess Smoothing tool**. To do this, select your data series, then click on the "Data" tab. In the "Data Tools" group, click on the "Lowess Smoothing" button. In the dialog box that appears, select the desired smoothing factor and click OK.

**How can I tone without losing my curves? ›**

**And Jordan's Top 5 Tips for Maintaining Your Curves:**

- WEIGHT TRAINING!
- Don't cut out carbs. Make sure you have a good intake of complex carbs.
- HIIT (high intensity interval training) instead of cardio.
- Low (5-8 reps per set) and slow repetitions.
- Do all of your cardio on an incline (Stairmaster, bike, or treadmill).

**Why are my curves uneven? ›**

The main reasons for uneven hips are: **scoliosis, which may be mild to severe and can change as a young person grows**. a difference in leg length that comes from posture and stance (this difference is functional rather than physical) a physical or structural difference in the lengths of your legs.

**How do you get big curves? ›**

**11 exercises to build hip muscles**

- Side lunges. This classic exercise will sculpt your hips by challenging your glutes to accelerate and decelerate your abductors, all while building strength. ...
- Curtsy lunges. ...
- Squats. ...
- Squats with sidekicks. ...
- Bulgarian split squats. ...
- Sumo walk. ...
- Clamshells. ...
- Hip lifts.

**Do you slow down before a curve? ›**

Look out for a recommended speed sign and slow down before you reach the curve to give you more control. The sharper the curve, the more you'll need to slow down. Check your mirrors for following traffic before you slow down for the curve. Position your car before the curve.

**Is Bell Curve grading fair? ›**

Instead of encouraging motivation and innovation, **grading on the Bell Curve has caused harm to both teachers and students in many ways**. Rather than giving students the grades that reflect their actual performance, the Bell Curve mandate forces professors to judge students' performances against those of others.

**How does bell curve grading work? ›**

**Professors can move up the average score by a set amount**. If the class average was 50%, for example, the professor might raise the average to 75%, effectively giving every student an extra 25 points out of 100. Similarly, if the average grade was a D, professors might change all D grades to C's.

**What is a bell curve for dummies? ›**

A bell curve is a type of graph that is used to visualize the distribution of a set of chosen values across a specified group that tend to have a central, normal values, as peak with low and high extremes tapering off relatively symmetrically on either side.

**Why is data not normally distributed? ›**

Data may not be normally distributed because **it actually comes from more than one process, operator or shift, or from a process that frequently shifts**.

**What sample size is a bell-shaped curve? ›**

In practice, some statisticians say that a sample size of 30 is large enough when the population distribution is roughly bell-shaped. Others recommend a sample size of **at least 40**.

### What are the limitations of a bell curve? ›

Limitations of a Bell Curve

In reality, **data are not perfectly normal**. Sometimes there is skewness, or a lack of symmetry, between what falls above and below the mean. Other times there are fat tails (excess kurtosis), making tail events more probable than the normal distribution would predict.

**What is the drawback of bell curve? ›**

Disadvantages of Bell Curve

Using the bell curve model in performance management **may be considered a rigid approach for rating employees**. Sometimes managers need to put employees in specific gradients just for the sake of bell curve requirements. This happens more often when the teams are small.

**Does the bell curve apply to everything? ›**

Known to statisticians as the Gaussian or Normal distribution, **the bell curve is routinely used to describe everything from the outcome of dice rolls to the weights, heights and IQs of randomly selected groups of people**.

**Is it good for data to be normally distributed? ›**

**It is the most important probability distribution in statistics because it accurately describes the distribution of values for many natural phenomena**. Characteristics that are the sum of many independent processes frequently follow normal distributions.

**How do you convert skewed data to normal distribution? ›**

**Okay, now when we have that covered, let's explore some methods for handling skewed data.**

- Log Transform. Log transformation is most likely the first thing you should do to remove skewness from the predictor. ...
- Square Root Transform. ...
- 3. Box-Cox Transform.

**Can I assume my data is normally distributed? ›**

In general, it is said that Central Limit Theorem “kicks in” at an N of about 30. In other words, **as long as the sample is based on 30 or more observations, the sampling distribution of the mean can be safely assumed to be normal**.

**Can Excel take area under a curve? ›**

Area Under Curve (AUC) is a widely used concept in data sciences in multiple fields. While the concept of Area Under Curve is quite simple – which is to calculate the total area covered between the curve/line and the axis – **there is no direct way to calculate this in Excel**.

**How do you show the equation of a curve in Excel? ›**

On the Layout tab, in the Analysis group, click Trendline, and then click More Trendline Options. To display the trendline equation on the chart, **select the Display Equation on chart check box**.

**How do you fit data into a curve? ›**

The most common way to fit curves to the data using linear regression is to **include polynomial terms, such as squared or cubed predictors**. Typically, you choose the model order by the number of bends you need in your line. Each increase in the exponent produces one more bend in the curved fitted line.

**How do you solve normal curve problems? ›**

**Step 1: Subtract the mean from the x value.** **Step 2: Divide the difference by the standard deviation**. The z score for a value of 1380 is 1.53. That means 1380 is 1.53 standard deviations from the mean of your distribution.

### What is a normal curve graph in Excel? ›

A normal distribution graph in excel is a continuous probability function and a common method to find the distribution of data. A formula is in-built in excel to find a normal distribution which is categorized under statistical functions. It completely depends on the mean and standard deviation.

**How to tell if data is normally distributed with mean and standard deviation? ›**

In order to be considered a normal distribution, **a data set (when graphed) must follow a bell-shaped symmetrical curve centered around the mean**. It must also adhere to the empirical rule that indicates the percentage of the data set that falls within (plus or minus) 1, 2 and 3 standard deviations of the mean.

**Should I transform non normal data? ›**

**No, you don't have to transform your observed variables just because they don't follow a normal distribution**. Linear regression analysis, which includes t-test and ANOVA, does not assume normality for either predictors (IV) or an outcome (DV).

**How do I make curves smooth in Excel? ›**

**Smooth angles of the line chart**

- Double-click the line you want to smooth.
- On the Format Data Series pane, switch to the Fill & Line tab, and select the Smoothed line check box. Done!

**How do you smooth distribution in Excel? ›**

Another way to smooth out data series in Excel is to **use the Lowess Smoothing tool**. To do this, select your data series, then click on the "Data" tab. In the "Data Tools" group, click on the "Lowess Smoothing" button. In the dialog box that appears, select the desired smoothing factor and click OK.

**How do you fix a bell curve problem? ›**

**All you have to do to solve the formula is:**

- Subtract the mean from X.
- Divide by the standard deviation.

**What is smoothing in Excel? ›**

Exponential Smoothing in Excel is **an inbuilt smoothing method used for Forecasting, Smoothing the data, trend projection**. To access, Exponential Smoothing in Excel, go to the Data menu tab and, from the Data Analysis option, choose Exponential Smoothing.

**How do I get rid of jagged lines in Excel? ›**

To remove gridlines, simply **select the View tab at the top of the screen and click to remove the check mark in the Gridlines box in the Show section of the ribbon**.

**What does it mean for a curve to be smooth? ›**

We say that a curve is smooth **if every point has a neighbourhood on which the curve is the graph of a differentiable function**. There are two obvious ways a curve can fail to be smooth: (1) It can intersect itself, or (2) it can have a cusp. Example of a smooth curve: Let S = {(x, y) | F(x, y) = y − x2 = 0}.

**How do I fix scaling in Excel? ›**

**Under Settings, click Custom Scaling > Custom Scaling Options.** **Click Page and in the Adjust to box, choose a percentage by which you want to increase or decrease the font size**. Review your changes in Print Preview and—if you want a different font size—repeat the steps.

### How do you blend data in Excel? ›

**Combine tables in Excel by column headers**

- On your Excel ribbon, go to the Ablebits tab > Merge group, and click the Combine Sheets button:
- Select all the worksheets you want to merge into one. ...
- Choose the columns you want to combine, Order ID and Seller in this example:
- Select additional options, if needed.

**How do you analyze a distribution in Excel? ›**

**Switch to the Data tab in the ribbon header interface, and then click on Data Analysis from the Analysis group**. If you don't have this option, navigate to File → Options → Add-ins and click on the Go button. Select Analysis ToolPak and click OK. The option should appear on your ribbon now.