## Excel CONFIDENCE.T function

The **CONFIDENCE.T** function uses a student’s distribution to calculate the confidence interval for a population mean.

**Tips:**

**Student’s Distribution**, you can visit this page on Wikipedia.

**Confidence Interval**, you can visit this page on Wikipedia.

**Note:** This **CONFIDENCE.T function** is only available in Excel 2010 and later versions.

#### Syntax

**=CONFIDENCE.T(alpha, standard_dev, size)**

#### Arguments

**Alpha**(required): The significance level used to calculate the confidence level, which equals to 1 – confidence level. A significance level of 0.05 equals to a confidence level of 95%.

**Standard_dev**(required): The population standard deviation for the data range.

**Size**(required): The sample size.

#### Remarks

**#NUM!**error occurs if either of the following condition is meet:

**"Alpha"**≤ 0 or ≥ 1;

**"Standard_dev"**≤ 0.

**#DIV/0!**error occurs if “size”=1;

**#VALUE!**error occurs when any argument is non-numeric;

**“size”**is not an integer, it will be truncated;

**Confidence Interval=Sample Mean ± CONFIDENCE**

#### Return value

It returns a numeric value.

#### Example

Supposing there is a list of values in the range B6:B16, to calculate the confidence interval for the population mean using a student's distribution, you need to do as follows.

Firstly, you need to provide the significance level (usually be 0.05, which equals to a confidence level of 95%), the standard deviation, the sample size, and the sample mean for the data range.

**=STDEV(B6:B16)**

**=COUNT(B6:B16)**

**=AVERAGE(B6:B16)**

1. Here we calculate the confidence value. Select a cell, for example E11, enter the formula below and press the **Enter** key to get the result.

**=CONFIDENCE.T(E6,E7,E8)**

As the interval is generally defined by its lower and upper bounds. The next steps will calculate the lower and upper bounds of the confidence interval.

2. Select a cell (say E12) to output the upper bound, enter the formula below and press the **Enter** key.

**=E9+E11**

2. Select a cell (say E13) to output the lower bound, enter the formula below and press the **Enter** key.

**=E9-E11**

Therefore, the confidence level is equal to 86.6765346 to 72.4143745.

#### Related Functions

** Excel CHISQ.INV function**

The CHISQ.INV function calculates the inverse of the left-tailed probability of the chi-squared distribution.

** Excel CHISQ.INV.RT function**

The CHISQ.INV.RT function calculates the inverse of the right-tailed probability of the chi-squared distribution.

** Excel CHISQ.TEST function**

The CHISQ.TEST function calculates the chi-squared distribution of two provided data sets (the observed and expected frequencies.

** Excel CONFIDENCE.NORM function**

The CONFIDENCE.NORM function uses a normal distribution to calculate the confidence interval for a population mean.

**The Best Office Productivity Tools**

#### Kutools for Excel - Helps You To Stand Out From Crowd

**Kutools for Excel Boasts Over 300 Features, Ensuring That What You Need is Just A Click Away...**

#### Office Tab - Enable Tabbed Reading and Editing in Microsoft Office (include Excel)

- One second to switch between dozens of open documents!
- Reduce hundreds of mouse clicks for you every day, say goodbye to mouse hand.
- Increases your productivity by 50% when viewing and editing multiple documents.
- Brings Efficient Tabs to Office (include Excel), Just Like Chrome, Edge and Firefox.