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T_CVF

Syntax | Arguments | Keywords | Examples | Version History | See Also

The T_CVF function computes the cutoff value V in a Student's t distribution with Df degrees of freedom such that the probability that a random variable X is greater than V is equal to a user-supplied probability P.


Note
T_CVF computes the cutoff value using the one-tailed probability. The cutoff value for the two-tailed probability, which is the probability that the absolute value of X is greater than V), can be computed as T_CVF(P/2, Df).

This routine is written in the IDL language. Its source code can be found in the file t_cvf.pro in the lib subdirectory of the IDL distribution.

Syntax

Result = T_CVF(P, Df)

Return Value

Returns the cutoff value.

Arguments

P

A non-negative single- or double-precision floating-point scalar, in the interval [0.0, 1.0], that specifies the probability of occurrence or success.

Df

A positive integer, single- or double-precision floating-point scalar that specifies the number of degrees of freedom of the Student's t distribution.

Keywords

None

Examples

Use the following command to compute the cutoff value in a Student's t distribution with five degrees of freedom such that the probability that a random variable X is greater than the cutoff value is 0.025.

result = T_CVF(0.025, 5)  
PRINT, result  

IDL prints:

2.57058  

Version History

4.0
Introduced

See Also

CHISQR_CVF, F_CVF, GAUSS_CVF, T_PDF

  IDL Online Help (June 16, 2005)