DAX Function Guide

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.

• 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).