# Excel T.TEST Function to perform Student’s T Test

This Excel tutorial explains how to use T.TEST Function to perform Independent Sample T Test and Paired-samples T Test.

## What is Independent T Test

In statistical inference, we are interested to know whether a small sample comes from a population. To inference using sample mean, when the population standard deviation and population mean are known, we can use Z test to interference the population mean from sample mean.

In reality, we do not have data of the whole population. Without the population standard deviation, we use T Test (also known as Student’s t Test) to interference the population mean from sample mean.

There are basically three kinds of T Test in statistics:

 One sample T Test Test whether a target mean value is equal to the population mean Independent sample T Test Test whether the population mean from two individual samples are equal. For two samples, you can also use One Way ANOVA, but ANOVA is not directional. Paired-samples T Test Test whether the population mean between paired observations are equal

Excel T.Test Function is used to find the P value of Independent Sample T Test and Paired-samples T Test.

## Syntax of Excel T.TEST Function

`T.TEST(array1,array2,tails,type)`
Array1 Required. The first data set.
Array2 Required. The second data set.
Tails Required. Specifies the number of distribution tails. If tails = 1, T.TEST uses the one-tailed distribution. If tails = 2, T.TEST uses the two-tailed distribution.
Type Required. The kind of t-Test to perform.

 1 Paired-samples T Test 2 Independent sample T Test with equal variance 3 Independent sample T Test with  unequal variance

## Example of Excel T.TEST Function

The below example shows employees’ salary in department A and department B.

The returned value of T.Test Function is a P value. If P value is <0.05, we can conclude the two sets of data have different mean; otherwise the two means are not significantly different.

If you want to understand the meaning of each test, please click the link below.

One sample T Test

Independent sample T Test

Paired-samples T Test

## Outbound References

https://support.office.com/en-us/article/T-TEST-function-D4E08EC3-C545-485F-962E-276F7CBED055

Wyman is a Human Resources professional based in Hong Kong, specialized in business analysis, project management, data transformation with Access and Excel.

He is also a:
- Microsoft Most Valuable Professional (Excel)
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- IBM SPSS Specialist