How to use the Z.TEST function in Excel Office 365?
Tags: tousetheztestfunctio, excel, excelfunctions
Published: 2021-08-21 10:39:39

---
title: How to use the Z.TEST function in Excel Office 365?
published: true
date: 2021-08-13 14:54:56 UTC
tags: ToUseTheZTESTFunctio,Excel,ExcelFunctions
canonical_url: https://geekexcel.com/how-to-use-the-z-test-function-in-excel-office-365/
---

The **Z.TEST function** returns the **probability** that the **sample mean** would be **greater than the average of observations** in the data set (array). In this article, we are going to see how to  **Use The Z.TEST Function In Excel Office 365.**  Let’s get into this article!! Get an official version of MS Excel from the following link: **[https://www.microsoft.com/en-in/microsoft-365/excel](https://www.microsoft.com/en-in/microsoft-365/excel)**

## Z.TEST Function syntax for one-tailed probability

```
=Z.TEST ( array , x , [sigma] )
```

## Z.TEST Function syntax for Two-tailed probability

```
=2 * MIN(Z.TEST ( array , x , [sigma] ), 1-Z.TEST ( array , x , [sigma] ) )
```

**Syntax Explanation:**

- **array** : sample data distribution
- **x:** value for which **z test** is evaluated
- **[sigma]** : [optional] The **population** (known) **standard deviation**. If omitted, the sample standard deviation is used.

## Example for one-tailed probability

- You need to create the **sample dataset Sales.**

![](https://geekexcel.com/wp-content/uploads/2021/08/Sample-data-set.png)<figcaption>Sample data set</figcaption>

- Then, you have to find the **Z test probability** for the given **hypothesized population mean** , assuming **one-tailed test**.
- Now, you need to use the following **formula** given below.

```
= Z.TEST( A2:A9 , C2 )
```

![](https://geekexcel.com/wp-content/uploads/2021/08/one-tailed-1024x329.png)<figcaption>One-tailed result</figcaption>

- You have to convert the **Z-Test value to percentage** , changing the **format of the cell to percentage** , because the probability value comes in **decimal** only.

![](https://geekexcel.com/wp-content/uploads/2021/08/in-percentage-1024x391.png)<figcaption>Change the value in percentage</figcaption>

## Example for two-tailed probability

- You need to calculate the **probability assuming two tailed distributions** having the **same parameters**.
- For that, you have to use the following **formula** given below.

```
= 2 * MIN( Z.TEST(A2:A9,C3) , 1 - Z.TEST(A2:A9,C3) )
```

![](https://geekexcel.com/wp-content/uploads/2021/08/two-tailed-1024x326.png)<figcaption>Two-tailed result</figcaption>

## Check the null hypothesis and alternate hypothesis

- For the **two-tailed distribution,** the **probability** gets **doubled** for the same sample dataset.
- Then, you need to **check the null hypothesis and alternate hypothesis**.
- Now, you have to calculate the **probability for the different hypothesized population mean** and **one-tailed** distribution.
- For that, you need to use the following formula given below.

```
 = Z.TEST( A2:A9 , C4 ) 
```

![](https://geekexcel.com/wp-content/uploads/2021/08/hypothesis-one-tailed-1024x322.png)<figcaption>One-tailed</figcaption>

- After that, you have to calculate the **probability for the different hypothesized population mean** and **two-tailed** distribution with same parameters.
- For that, you need to use the following formula given below.

```
= 2 * MIN( Z.TEST(A2:A9,C5) , 1 - Z.TEST(A2:A9,C5) )
```

![](https://geekexcel.com/wp-content/uploads/2021/08/hypothesis-two-tailed-1024x322.png)<figcaption>Two-tailed</figcaption>

## Closure:

This article gives you clarity on **How to Use The Z.TEST Function In Excel Office 365.** Is this article helpful? Don’t forget to share your valuable  **queries/suggestions**  in the below comment box & also drop your  **worthwhile feedback**.

Thanks for visiting **[Geek Excel!!](https://geekexcel.com/)** Keep Learning with us!!

**Read Next:**

- **[Excel Formulas to Generate Random Number Weighted Probability!!](https://geekexcel.com/excel-formulas-to-generate-random-number-weighted-probability/)**
- **[Insert Sheet in Microsoft Excel 2007?](https://geekexcel.com/insert-sheet-in-microsoft-excel-2007/)**
- **[Create a Normal Distribution Chart (Bell Curve) in Excel](https://geekexcel.com/how-to-create-a-normal-distribution-chart-bell-curve-in-excel/)**
- **[How to Format Text in Microsoft Excel 2013?](https://geekexcel.com/how-to-format-text-in-microsoft-excel-2013/)**
- **[Formulas to Find the Smaller of Two Values!!](https://geekexcel.com/excel-formulas-find-the-smaller-of-two-values/)**