---
name: "pchisq"
section: "3m"
platform: "linux"
package: "iraf"
version: "2.11.3-2"
release: "Debian 3.0 (Woody)"
platforms: ["linux"]
url: "https://new.carta.tech/pchisq"
---

# pchisq(3m)

## NAME

pchisq

## DESCRIPTION

function pchisq.f

source\
   Bevington, pages 192-193.

purpose\
   evaluate probability for exceeding chi square

usage\
   result = pchisq (chisqr, nfree)

description of parameters\
   chisqr - comparison value of reduced chi square\
   nfree  - number of degrees of freedom

subroutines and function subprograms required\
   gamma (x)\
     calculates gamma function for integers and 1/2-integers

comments\
   calculation is approximate for nfree odd and\
     chi square greater than 50