TINV

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 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 is calculated as TINV = p( t<X ), where X is a random variable that follows the t-distribution.
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).

TINV uses an iterative technique for calculating the function. Given a probability value, TINV iterates until the result is accurate to within ± 3x10^-7. If TINV does not converge 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 spreadsheet.

How?

Create a blank spreadsheet.
Select the example in the Help topic.

Selecting an example from Help
Press CTRL+C.
In the spreadsheet, select cell A1, and press CTRL+V.
To switch between viewing the formula that returns the result and the result in the cell, select the cell and press F2 and then ENTER, or click Commands and Options on the spreadsheet toolbar, click the Formula tab, and look in the Formula in active cell (active cell) box.

Data	Description
0.054645	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 (1.959997462)