TINV

See Also

Returns the t-value of the Student's t-distribution as a function of the probability and the degrees of freedom.

Syntax

TINV(probability,degrees_freedom)

Probability    is the probability associated with the two-tailed Student's t-distribution.

Degrees_freedom    is the number of degrees of freedom with which to characterize the distribution.

Remarks

• If either argument is nonnumeric, TINV returns the #VALUE! error value.
• If probability < 0 or if probability > 1, TINV returns the #NUM! error value.
• If degrees_freedom is not an integer, it is truncated.
• If degrees_freedom < 1, TINV returns the #NUM! error value.
• TINV 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 TINV(0.05,10), which returns 2.28139. The one-tailed value for the same probability and degrees of freedom can be calculated with TINV(2*0.05,10), which returns 1.812462.

  Note   In some tables, probability is described as (1-p).

  Given a value for probability, TINV seeks that value x such that TDIST(x, degrees_freedom, 2) = probability. Thus, precision of TINV depends on precision of TDIST. TINV uses an iterative search technique. If the search has not converged after 100 iterations, the function returns the #N/A error value.

Example

The example may be easier to understand if you copy it to a blank worksheet.

How?