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

# xfit(3m)

## NAME

xfit

## DESCRIPTION

subroutine xfit.f

source\
   Bevington, page 76.

purpose\
   calculate mean and estimated errors for set of data points

usage\
   call xfit (x, sigmax, npts, mode, xmean, sigmam, sigma)

description of parameters\
   x      - array of data points\
   sigmax - array of standard deviations for data points\
   npts   - number of data points\
   mode   - determines method of weighting\
            \+1 (instrumental) weight(i) = 1./sigmax(i)\*\*2\
             0 (no weighting) weight(i) = 1.\
            \-1 (statistical)  weight(i) = 1.\
   xmean  - weighted mean\
   sigmam - standard deviation of mean\
   sigma  - standard deviation of data

subroutines and function subprograms required\
   none