Returns the two-tailed inverse of the Student's t-distribution.
The probability that is associated with the Student's t-distribution.
The number of degrees of freedom with which to characterize the distribution.
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,2) = probability. Thus, precision of T.INV.2T depends on precision of T.DIST.2T.
To make the following example easier to understand, you can copy the data to a blank sheet and then enter the function underneath the data. Do not select the row or column headings (1, 2, 3... A, B, C...) when you copy the sample data to a blank sheet.