NAME
fchisq
DESCRIPTION
function fchisq.f
source
Bevington, page 194.
purpose
evaluate reduced chi square for fit of data
fchisq = sum ((y-yfit)**2 / sigma**2) / nfree
usage
result = fchisq (y, sigmay, npts, nfree, mode, yfit)
description of parameters
y - array of data points
sigmay - array of standard deviations for data points
npts - number of data points
nfree - number of degrees of freedom
mode - determines method of weighting least-squares fit
+1 (instrumental) weight(i) = 1./sigmay(i)**2
0 (no weighting) weight(i) = 1.
-1 (statistical) weight(i) = 1./y(i)
yfit - array of calculated values of y
subroutines and function subprograms required
none