﻿ TINV function

# 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.

How to copy an example

1. Create a blank workbook or worksheet.

2. Select the example in the Help topic.

Note   Do not select the row or column headers.

Selecting an example from Help

3. Press CTRL+C.

4. In the worksheet, select cell A1, and press CTRL+V.

5. To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Formulas tab, in the Formula Auditing group, click the Show Formulas button.

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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

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