## How does the T.DIST function (DAX) work?

The T.DIST function (DAX) returns the Student’s left-tailed t-distribution.

## T.DIST Formula Syntax

T.DIST(
X,Deg_freedom,Cumulative
)

## How do you use the T.DIST function?

The t-distribution function is used in the hypothesis testing of small sample data sets. Use this function in place of a table of critical values for the t-distribution.

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## Considerations when using the T.DIST function

• If any argument is non-numeric, TDIST returns the #VALUE! error value.
• If Deg_freedom < 1, TDIST returns the #NUM! error value.
• The Deg_freedom and Tails arguments are truncated to integers.
• If Tails is any value other than 1 or 2, TDIST returns the #NUM! error value.
• If x < 0, then TDIST returns the #NUM! error value.
• If Tails = 1, TDIST is calculated as TDIST = P( X>x ), where X is a random variable that follows the t-distribution. If Tails = 2, TDIST is calculated as TDIST = P(|X| > x) = P(X > x or X < -x).
• Since x < 0 is not allowed, to use TDIST when x < 0, note that TDIST(-x,df,1) = 1 – TDIST(x,df,1) = P(X > -x) and TDIST(-x,df,2) = TDIST(x,df,2) = P(|X| > x).

## Formula examples using the T.DIST function

EVALUATE { T.DIST(60, 1, TRUE) }

=TDIST(A2,A3,2)

=TDIST(A2,A3,1)

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