TINV function

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.

ShowHow to copy an example

  • Create a blank workbook or worksheet.
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 Note   Do not select the row or column headers.

Selecting an example from Help

Selecting an example from Help
  • Press CTRL+C.
  • In the worksheet, select cell A1, and press CTRL+V.
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A B
Data Description
0.054644927 Probability associated with the two-tailed Student's t-distribution
60 Degrees of freedom
Formula Description (Result)
=TINV(A2,A3) t-value of the Student's t-distribution for the terms above (1.959999998)
 
 
Applies to:
Excel 2007