T.DIST

Student's t distribution at a value, as a density or a left-tail probability.

Group: Statistics. Compatible with DAX.

Syntax

T.DIST ( <X>, <Deg_freedom>, <Cumulative> )

Parameter	Type	Description
`X`	Number	The t value.
`Deg_freedom`	Whole number	The degrees of freedom, 1 or more; rounded to a whole number.
`Cumulative`	Boolean	TRUE for the cumulative probability, the chance of a value up to x; FALSE for the density at x.

Number. Student's t density at x, or the left-tail probability up to x.

For a test's p-value, T.DIST.2T (both tails) or T.DIST.RT (the right tail) is usually what is wanted.
Degrees of freedom that are not whole are rounded to the nearest whole number: 2.5 counts as 3.
With many degrees of freedom it comes close to NORM.S.DIST.

EVALUATE
ROW (
    "Density", T.DIST ( 1.5, 10, FALSE ),
    "Left tail", T.DIST ( 1.5, 10, TRUE )
)

Density	Left tail
0.127444794287092	0.91774633677728

EVALUATE
ROW (
    "t, 1000 df", T.DIST ( 1.96, 1000, TRUE ),
    "Normal", NORM.S.DIST ( 1.96, TRUE )
)

t, 1000 df	Normal
0.974863407522134	0.97500210485178

Last updated 3 November 2026 · OpenBI Studio 0.3.74