# Documentation/Calc Functions/T.DIST.2T

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T.DIST.2T

## Category:

Statistical Analysis

## Summary:

Calculates two-tailed test values for the Student's t-distribution (often known more simply as just the t-distribution). The Student's t-distribution is often used to test a hypothesis about a population’s mean when the population’s standard deviation is not known. The Student’s t-distribution can be used with any statistic whose distribution is approximately normal.

## Syntax:

T.DIST.2T(Number; DegreesFreedom)

## Returns:

Returns a positive real number in the range 0 to 1 (exclusive) representing the total area under the two tails of the probability distribution function of the specified Student’s t-distribution, lying above the given Number and below -Number.

## Arguments:

Number is a non-negative real number or a reference to a cell containing that number which is the value for which the two-tailed test value for the Student's t-distribution is to be calculated.

DegreesFreedom is a positive integer value or a reference to the cell containing that number which is the number of degrees of freedom for the Student’s t-distribution.

• If Number is less than 0 then the function returns an error value.
• If DegreesFreedom is less than 1 then the function returns an error value.
• If DegreesFreedom is a non-integer value then the function uses its floor value, i.e. it is truncated to an integer.

## Additional details:

• The formula for T.DIST.2T is:

where

Here, x is the Number, df is DegreesFreedom and tails is equal to 2.

• It is such that T.DIST.2T(x ,y) = 2 * T.DIST.RT(x, y) and that T.DIST.2T(x, y) = TDIST(x, y, 2).
• For more details about the Student's t-distribution, visit Wikipedia.

## Examples:

Formula Description Returns
=T.DIST.2T(7;3) The function calculates the two-tailed test value for the Student's t-distribution for the given data. 0.005986255697707
=T.DIST.2T(5.8;1.5) The function calculates the two-tailed test value for the Student's t-distribution for the given data. Here DegreesFreedom is non-integer value 1.5 so the function truncates it to integer 1. 0.108693411464525
=T.DIST.2T(5.8;0.9) The function returns an error value since the DegreesFreedom is less than 1. Err:502
=T.DIST.2T(-5.8;1.5) The function returns an error value since the Number is less than 0. Err:502

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T.DIST.2T