TDIST
TheTDIST
function calculates the probability associated with a Student's tTest. It returns the probability that the difference between two data sets is greater than or equal to a certain value. This function is commonly used in hypothesis testing.
 How to use
TDIST
formula?  Examples of using
TDIST
formula TDIST
formula not working? Similar formulas to
TDIST
Usage
Use the TDIST
formula with the syntax shown below, it has 3 required parameters:
 x (required):
The value at which to evaluate the tdistribution.  degrees_freedom (required):
The degrees of freedom for the tdistribution.  tails (required):
The number of tails to use in the distribution. Must be either 1 or 2.
Examples
Here are a few example use cases that explain how to use theTDIST
formula in Google Sheets.
Testing the difference between two means
Suppose we want to test whether the mean difference between two sets of data is statistically significant. We can use the TDIST
function to calculate the probability of observing a difference as extreme or more extreme than the one we observed, assuming that the null hypothesis (that the means are equal) is true.
Calculating critical values
In hypothesis testing, we often need to find the critical value for a given significance level and degrees of freedom. The TDIST
function can be used to calculate this value.
Onetailed vs. twotailed tests
The TDIST
function allows you to specify whether you want to perform a onetailed or twotailed test. This is important because it affects how the probability is calculated.
Common Mistakes
TDIST
not working? Here are some common mistakes people make when using the TDIST
Google Sheets Formula:
Not specifying the number of tails
The TDIST
function requires the user to specify the number of tails. Failure to do so can result in incorrect results if the default value is not what is desired.
Using incorrect degrees of freedom
The degrees of freedom parameter is critical to the calculation of the Student's tdistribution. Using an incorrect value can lead to incorrect results.
Related Formulas
The following functions are similar to TDIST
or are often used with it in a formula:

TTEST
The
TTEST
formula is a statistical formula used to determine the probability of two sample means being equal. It is commonly used in hypothesis testing to determine if there is a significant difference between two sets of data. The formula returns the probability value associated with a ttest, which can be used to determine if the null hypothesis should be rejected or not. 
TINV
The
TINV
function returns the inverse of the Student's tdistribution for a given probability and degrees of freedom. This function is commonly used in statistical analysis to determine the value of t for a given probability and degrees of freedom. 
CONFIDENCE
The
CONFIDENCE
function calculates the confidence value for a population mean. This is often used in statistical analysis to determine the range in which a population mean is likely to fall. The function takes three parameters: the significance level (alpha), the standard deviation of the population (standard_deviation), and the size of the population (pop_size). 
STDEV
The
STDEV
function calculates the standard deviation of a set of numbers. It measures the amount of variation or dispersion of a set of values from the average (mean) value. It is commonly used in statistics to determine the spread of a data set. The values can be supplied as individual cells, ranges, or constants.
Learn More
You can learn more about the TDIST
Google Sheets function on Google Support.