**Excel** is the most widely used tool for dealing with massive datasets. We can perform myriads of tasks of multiple dimensions in **Excel**. In this article, I will show you how to plot **Weibull Distribution** in **Excel**.

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## Introduction to Weibull Distribution

The **Weibull Distribution** is a continuous** probability distribution** that is used to analyze life data, model failure times, and assess the reliability of access products. This** distribution** can be used largely in different fields to analyze data.

**Reliability Function R(t) = e^-[{(t-γ)/α}^β]**

Where,**β = Shape Parameter**

**α = Scale Parameter**

**γ = Location Parameter.**This is usually

**0**.

From

**R(t)**, we can get the Failure function

**F(t)**

**F(t) = 1-R(t)**

After calculation, we get**ln(ln(1/(1-F(t))) = βlnt-βlnα**This resembles the

**y=mx+c**equation

## 4 Quick Steps to Plot Weibull Distribution in Excel

This is the dataset for today’s article. We have the instances of failure and the number of days for the failure. For example, the 1st failure occurs after 400 days, 2nd one after 820 days.

I will use this data to get the **Weibull Distribution** and understand the failure rate.

### Step 1: Calculate Median Rank

The first step is to calculate the median rank. To calculate this, we will use Bernard’s approximation.

- Go to
**D5**and write down the following formula

`=(B5-0.3)/($B$14+0.4)`

- Then, press
**ENTER**to get the output.

- After that, use the
**Fill Handle**to**AutoFill**up to**D14**.

### Step 2: Determine Natural Logarithm

The next step is to calculate the natural logarithm as per the requirement. First, we will determine the logarithm of days. To do so,

- Go to
**E5**and write down the following formula

`=LN(C5)`

- Then, press
**ENTER**to get the output.

- After that, use
**Fill Handle**to**AutoFill**up to**E14**.

- In a similar way, we will fill up the next column. The formula in
**F5**will be

`=LN(LN(1/(1-D5)))`

- Then, press
**ENTER**to get the output.

- After that, use
**Fill Handle**to**AutoFill**up to**F14**.

**Read More:** **How to Plot Normal Distribution in Excel (With Easy Steps)**

### Step 3: Plot Distribution Chart

The next step is to plot a chart using **ln(days)** as x-axis and **ln(ln(1/(1-F(t)))) **as y-axis. To do so,

- Select
**E4:F14**.

- Then, go to the
**Insert** - After that, choose the
**Scatter** - Finally, select the one you like.

**Excel**will create a scatter plot.- Rename the plot to Weibull
**Distribution**.

**Read More: How to Make a Cumulative Distribution Graph in Excel**

### Step 4: Compare Equation to Determine Coefficients

Now, we will determine the parameters. We will get the trendline equation and compare it with the equation **ln(ln(1/(1-F(t))) = βlnt-βlnα**

- Go to
**Chart Design**. - Then, go to
**Add Chart Element**. - After that choose a
**Trendline**.

**Excel**will add a trendline.and__Select the trendline__**right-click**your mouse.- Then, select
**Format Trendline**.

- After that, mark the box for
**Display Equation on Chart**.

**Excel**will show the equation.

- The equation is
**y=1.9551x-14.663**. After comparing with**ln(ln(1/(1-F(t))) = βlnt-βlnα,**we get**β = 1.9551****βlnα = 14.663**

- Using these values, we get
**α = 1807.811**

** **

- So, the
**Reliability Function**becomes

**R(t) = e^-[(t/1807.811)^1.9551]**

**Read More: How to Make a t-Distribution Graph in Excel (with Easy Steps)**

## Things to Remember

The shape parameter indicates the failure rate.

- If
**β < 1**, then the failure rate decreases with time - If
**β****= 1**, then the failure rate is constant - If
**β > 1**, the failure rate increases with time

Use **absolute reference** to lock a cell.

## Conclusion

In this article, I have explained how to plot **Weibull Distribution** in **Excel**. I hope it helps everyone. If you have any suggestions, ideas, or feedback, please feel free to comment below. Please visit **Exceldemy** for more useful articles like this.