The Excel T.INV Function

Related Function:
T.INV.2T Function


The T.INV function calculates the one-tailed inverse Student's T-Distribution. This function is new to Excel 2010, and so is not availiable in earlier versions of Excel.

The T.INV function is not to be confused with the TINV function, which is available in earlier versions of Excel. The TINV function calculates the two-tailed inverse Student's T-Distribution and is replaced in Excel 2010 by the T.INV.2T function.

Basic Description

The Excel T.INV function calculates the two-tailed inverse Student's T Distribution, which is a continuous probability distribution that is frequently used for testing hypotheses on small sample data sets.

The format of the function is :

T.INV( probability, degrees_freedom )

Where the function arguments are:

probability - The probability (between 0 and 1) for which you want to evaluate the inverse of the two-tailed Student's T Distribution.
degrees_freedom - The number of degrees of freedom (must be ≥ 1)

T.Inv Function Examples

Plot of Inverse of Left-Tailed Student's T Distribution with 10 Degrees of Freedom
Left-Tailed Inverse Student's T-Distribution with 10 Degrees of Freedom

The chart on the right shows the left-tailed Inverse Student's T Distribution with 10 degrees of freedom.

If you want to calculate the value of this function for a probability of 0.25, this can be done using the Excel T.Inv function, as follows:

=T.INV( 0.25, 10 )

This gives the result -0.699812061.

Further information and examples of the Excel T.Inv function can be found on the Microsoft Office website.

T.Inv Function Errors

If you get an error from your Excel T.Inv function this is likely to be one of the following :

Common Errors
#NUM! - Occurs if either:
- The supplied probability argument is ≤ 0 or > 1
- the supplied degrees_freedom argument is < 1
#VALUE! - Occurs if either of the supplied arguments are non-numeric
Return to the Excel Statistical Functions Page

Return to the List of All Built-In Excel Functions