TDIST

Syntax:

TDIST ( x , degrees-freedom , distribution-tails )

Description: Computes the Percentage Points (probability) for the Student t-distribution where a numeric value, x, is a calculated value of t for which the Percentage Points are to be computed.

Mathematical Formula:

If distribution-tails = 1, TDIST = P( X>x ), where X is a random variable that follows the t-distribution.

If distribution-tails = 2, TDIST = P(|X| > x) = P(X > x or X < -x)

Arguments:

Name	Type	Description
x	number	The value at which to evaluate the distribution.
degrees-freedom	number	The number of degrees of freedom, truncated to an integer.
distribution-tails	number	The number of distribution tails to return, truncated to an integer. If 1, `TDIST` returns the one-tailed distribution. If 2, `TDIST` returns the two-tailed distribution.

Return Type and Value: number – The Percentage Points (probability) for the Student t-distribution.

However, if

degrees-freedom < 1, #NUM! is returned.
tails has any value other than 1 or 2, #NUM! is returned.
x < 0, #NUM! is returned.

example: