Description

The T.INV.2T function returns the two-tailed inverse of the Student's t-distribution.

Syntax

T.INV.2T (probability,deg_freedom)

Argument	Description	Required/ Optional
Probability	The probability associated with the Student's tdistribution.	Required
Deg_freedom	An integer indicating the number of degrees of freedom.	Required

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 t-distribution and P(|X| > t) = P(X < -t or X > t).
A one-tailed t-value can be returned by replacing probability with 2*probability. For a probability of 0.05 and degrees of freedom of 10, the two-tailed value is calculated with T.INV.2T (0.05, 10), which returns 2.28139. The one-tailed 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) = probability. Thus, precision of T.INV.2T depends on precision of T.DIST.2T.

Excel 2010, Excel 2013, Excel 2016