The image above represents Poisson probability distribution. To calculate Poisson probability distribution, two essential parameters are needed: Mean** of the Theoretical Distribution (μ)** and **Number of successes of event A (r).**

The formula for Poisson probability distribution:

P(x = r) = ^{e-μ(μr)} ⁄ _{r!}

Where;

P(x = r) = Poisson Probability Distribution

r = Number of Successes of Event A

μ = Mean of the Theoretical Distribution

Let’s solve an example;

Find the poisson probability distribution when the mean of the theoretical distribution is 12 and the number of successes of event A is 6.

This implies that;

r = Number of Successes of Event A = 6

μ = Mean of the Theoretical Distribution = 12

P(x = r) = ^{e-μ(μr)} ⁄ _{r!}

P(x = r) = ^{e-12(12)6} ⁄ _{6!}

So, P(x = r) = ^{(0.00000614)(2985984)} ⁄ _{(720)}

P(x = r) = 0.025

Therefore, the **Poisson probability distribution **is **0.025.**

Read more: How to Calculate and Solve for General Binomial Distribution | Probability

**How to Calculate Poisson Probability Distribution Using Nickzom Calculator**

Nickzom Calculator – **The Calculator Encyclopedia** is capable of calculating the poisson probability distribution.

To get the answer and workings of the poisson probability distribution using the **Nickzom Calculator – The Calculator Encyclopedia. **First, you need to obtain the app.

You can get this app via any of these means:

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**Web** – https://www.nickzom.org/calculator-plus

To get access to the **professional **version via web, you need to **register** and **subscribe **for** NGN 1,500 **per** annum** to have utter access to all functionalities.

You can also try the **demo **version via https://www.nickzom.org/calculator

**Android (Paid)** – https://play.google.com/store/apps/details?id=org.nickzom.nickzomcalculator

**Android (Free)** – https://play.google.com/store/apps/details?id=com.nickzom.nickzomcalculator

**Apple (Paid)** – https://itunes.apple.com/us/app/nickzom-calculator/id1331162702?mt=8

Once, you have obtained the calculator encyclopedia app, proceed to the **Calculator Map, **then click on **Probability**** **under **Mathematics****.**

Now, Click on **Poisson Probability Distribution**** **under **Probability**

The screenshot below displays the page or activity to enter your values, to get the answer for the poisson probability distribution according to the respective parameters which are the **Mean of the Theoretical Distribution (μ) and Number of successes of event A (r).**

Now, enter the values appropriately and accordingly for the parameters as required by the **Mean of the Theoretical Distribution (μ)** is **12**** and Number of successes of event A (r)** is **6.**

Finally, Click on Calculate

As you can see from the screenshot above, **Nickzom Calculator**– The Calculator Encyclopedia solves for the poisson probability distribution and presents the formula, workings and steps too.