Returns the twotailed inverse of the Student's tdistribution.
Syntax
T.INV.2T(probability,deg_freedom)
The T.INV.2T function syntax has the following arguments (argument: A value that provides information to an action, an event, a method, a property, a function, or a procedure.):
 Probability Required. The probability associated with the Student's tdistribution.
 Deg_freedom Required. The number of degrees of freedom with which to characterize the distribution.
Remarks
 If either argument is nonnumeric, T.INV.2T returns the #VALUE! error value.
 If probability <= 0 or if probability > 1, T.INV.2T returns the #NUM! error value.
 If deg_freedom is not an integer, it is truncated.
 If deg_freedom < 1, T.INV.2T returns the #NUM! error value.
 T.INV.2T returns that value t, such that P(X > t) = probability where X is a random variable that follows the tdistribution and P(X > t) = P(X < t or X > t).
 A onetailed tvalue can be returned by replacing probability with 2*probability. For a probability of 0.05 and degrees of freedom of 10, the twotailed value is calculated with T.INV.2T(0.05,10), which returns 2.28139. The onetailed value for the same probability and degrees of freedom can be calculated with T.INV.2T(2*0.05,10), which returns 1.812462.
Given a value for probability, T.INV.2T seeks that value x such that T.DIST.2T(x, deg_freedom, 2) = probability. Thus, precision of T.INV.2T depends on precision of T.DIST.2T.
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 Online, 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 Online, 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.
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After you copy the example to a blank worksheet, you can adapt it to suit your needs.

A 
B 
Data 
Description 
0.546449 
Probability associated with the twotailed Student's tdistribution 
60 
Degrees of freedom 
Formula 
Description (Result) 
=T.INV.2T(A2,A3) 
Tvalue of the Student's tdistribution for the terms above (0.606533076) 
