PROBT Function

PROBT Function

Returns the probability from a t distribution

Category: Probability

See: 'CDF Function' on page 418, 'PDF Function' on page 695

Syntax

PROBT ( x,df <, nc >)

Arguments

x

• is a numeric random variable.

df

• is a numeric degrees of freedom parameter.

• Range: df > 0

nc

• is an optional numeric noncentrality parameter.

Details

The PROBT function returns the probability that an observation from a Student's t distribution, with degrees of freedom df and noncentrality parameter nc , is less than or equal to x . This function accepts a noninteger degree of freedom parameter df . If the optional parameter, nc , is not specified or has the value 0, the value that is returned is from the central Student's t distribution.

The significance level of a two-tailed t test is given by

 p=(1-probt(abs(x),df))*2; 

Examples

SAS Statements	Results
x=probt(0.9,5);	0.7953143998