Table of Contents
This guide provides a practical overview of CONFIDENCE. T Function, including its main features, benefits, limitations, and important considerations.

Description: The function returns the confidence interval of the population by using the Student's t-distribution. Support functions from Excel 2010 onwards.
Syntax: CONFIDENCE. NORM (alpha, standard_dev, size)
Inside:
- alpha: The critical level to calculate the confidence level, with confidence level = 100 * (1- alpha) , is the required parameter .
- standard_dev: The overall standard deviation for the data range, and considered to have been determined, is the required parameter.
- size: Sample size , is a required parameter.
Attention:
- If any of the parameters' values are not numeric -> the function returns the #VALUE! Error value .
- If alpha ≤ 0 or alpha ≥ 1 -> the function returns the #NUM! Error value
- If standard_dev ≤ 0 -> the function returns the #NUM! Error value
- If size is not an integer -> it is truncated to an integer.
- If size = 1 -> the function returns the # DIV / 0 error value !
For example:
Calculate the average overall confidence interval based on the Student's t-distribution with the data in the table below:

- In the cell to calculate, enter the formula: = CONFIDENCE. T (D6, D7, D8)

- Press Enter -> the overall confidence interval for the population is:

- Where alpha ≤ 0 or alpha ≥ 1 -> the function returns the #NUM! Error value

- Where size = 1 -> the function returns the error value #NUM!

Above are instructions and some specific examples when using the CONFIDENCE. T function in Excel.
Good luck!
FAQ
What does the CONFIDENCE. T Function function do in Excel?
The CONFIDENCE. T Function function performs the calculation described in this guide. Use the correct arguments and compatible data types for reliable results.
How do I enter the CONFIDENCE. T Function function correctly?
Start with an equals sign, enter CONFIDENCE. T Function, add the required arguments inside parentheses, and confirm that cell references and separators are correct.
Why does the CONFIDENCE. T Function function return an error?
Common causes include missing arguments, invalid data types, incorrect cell references, unsupported values, or regional separator settings.
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