CONFIDENCE.T
TheCONFIDENCE.T
function calculates the confidence interval for a onetailed Student's tdistribution. This function is commonly used in statistics to determine the range of values likely to contain an unknown population parameter with a certain level of confidence. The result of the function is the range of values around the sample mean, where the population mean is expected to fall within a certain confidence level.
 How to use
CONFIDENCE.T
formula?  Examples of using
CONFIDENCE.T
formula CONFIDENCE.T
formula not working? Similar formulas to
CONFIDENCE.T
Usage
Use the CONFIDENCE.T
formula with the syntax shown below, it has 3 required parameters:
 alpha (required):
The significance level used to compute the confidence level. Must be between 0 and 1.  standard_deviation (required):
The standard deviation of the population.  size (required):
The sample size.
Examples
Here are a few example use cases that explain how to use theCONFIDENCE.T
formula in Google Sheets.
Calculating the confidence interval for a sample mean
Suppose you have a sample of size 30, with a mean of 100 and a standard deviation of 10. You want to calculate the 95% confidence interval for the population mean. You can use the CONFIDENCE.T
function with alpha=0.05
, standard_deviation=10
, and size=30
.
Testing the difference between two means
Suppose you have two samples, with means of 100 and 110, and standard deviations of 10 and 12, respectively. You want to test if the difference between the two means is statistically significant at a 90% confidence level. You can use the CONFIDENCE.T
function to calculate the confidence interval for the difference in means, and check if it includes 0.
Estimating the sample size
Suppose you want to estimate the sample size required to estimate the population mean with a margin of error of 5, and a 95% confidence level. You can use the CONFIDENCE.T
function to solve for size
.
Common Mistakes
CONFIDENCE.T
not working? Here are some common mistakes people make when using the CONFIDENCE.T
Google Sheets Formula:
Incorrect order of arguments
Make sure to enter the arguments in the correct order: alpha, standard deviation, size.
Invalid alpha value
The alpha value must be between 0 and 1. Check that the value entered is within this range.
Invalid standard deviation
Make sure that the standard deviation value is positive and that it is the correct value for the population or sample being analyzed.
Invalid sample size
Make sure that the sample size entered is a positive integer and large enough for the confidence interval desired.
Related Formulas
The following functions are similar to CONFIDENCE.T
or are often used with it in a formula:

T.DIST
The
T.DIST
function returns the probability of a Student's tdistribution with a specified degrees of freedom. This function is usually used in hypothesis testing to determine the probability that a sample mean is within a specified range of values. 
T.DIST.2T
The
T.DIST.2T
function returns the twotailed probability of the Student's tdistribution. This function is commonly used in hypothesis testing to determine if two sets of data have different means. It is also used in confidence interval estimation, where it calculates the probability that the difference between two population means falls within a specified range. 
T.INV
The
T.INV
function returns the inverse of the Student's tdistribution for the provided probability and degrees of freedom. This function is commonly used to calculate a critical value from the tdistribution when working with small sample sizes. 
T.INV.2T
The
T.INV.2T
function returns the twotailed inverse of the tdistribution. This is commonly used in hypothesis testing to determine the critical value of t for a given level of significance and degrees of freedom.
Learn More
You can learn more about the CONFIDENCE.T
Google Sheets function on Google Support.