T.DIST.2T function
Returns the twotailed Student's tdistribution.
The Student's tdistribution is used in the hypothesis testing of small sample data sets. Use this function in place of a table of critical values for the tdistribution.
Syntax
T.DIST.2T(x,deg_freedom)
The T.DIST.2T function syntax has the following arguments:

X Required. The numeric value at which to evaluate the distribution.

Deg_freedom Required. An integer indicating the number of degrees of freedom.
Remarks

If any argument is nonnumeric, T.DIST.2T returns the #VALUE! error value.

If deg_freedom < 1, T.DIST.2T returns the #NUM! error value.

If x < 0, then T.DIST.2T returns the #NUM! error value.
Example
The example may be easier to understand if you copy it to a blank worksheet.
How do I copy an example?

Select the example in this article. If you are copying the example in Excel Web App, copy and paste one cell at a time.
Important Do not select the row or column headers.
Selecting an example from Help

Press CTRL+C.

Create a blank workbook or worksheet.

In the worksheet, select cell A1, and press CTRL+V. If you are working in Excel Web App, repeat copying and pasting for each cell in the example.
Important For the example to work properly, you must paste it into cell A1 of the worksheet.

To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Formulas tab, in the Formula Auditing group, click the Show Formulas button.
After you copy the example to a blank worksheet, you can adapt it to suit your needs.


Note To view the result as a percentage, select the cell, and then on the Home tab, in the Number group, click the arrow next to Number Format, and click Percentage.