Returns the two-tailed inverse of the Student's t-distribution.
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 t-distribution.
- Deg_freedom Required. The number of degrees of freedom with which to characterize the distribution.
- 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, 2) = probability. Thus, precision of T.INV.2T depends on precision of T.DIST.2T.
The example may be easier to understand if you copy it to a blank worksheet.
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||Probability associated with the two-tailed Student's t-distribution
||Degrees of freedom
||T-value of the Student's t-distribution for the terms above (0.606533076)