The CHISQR_CVF function computes the cutoff value *V* in a chi-square 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*.

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

## Examples

Use the following command to compute the cutoff value in a chi-square distribution with three degrees of freedom such that the probability that a random variable X is greater than the cutoff value is 0.100. The result should be 6.25139.

PRINT, CHISQR_CVF(0.100, 3)

IDL prints:

6.25139

## Syntax

*Result* = CHISQR_CVF(*P*,* Df*)

## Return Value

Returns computes the cutoff value *V* in a chi-square 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.*

## 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 chi-square distribution.

## Keywords

None.

## Version History

4.0 |
Introduced |

## See Also

CHISQR_PDF, F_CVF, GAUSS_CVF, T_CVF