hi(adsbygoogle = window.adsbygoogle || []).push({});

i have some data (star counts) and i have a model and i want to perform min chi squared

so if i call my data di, and my model mi with std dev = [itex]\sigma[/itex]i = 1

then [itex]\chi^2 = \sum \frac{(di - mi)^2}{\sigma i^2}[/itex]

no my model is this mi = bi - Fo where bi is the background which has been assumed to be 5, and Fo is some constant flux. from this i am thus assuming that the data is ecpected to be a flat line.

Now i want to determine the min ch squared estimate for Fo, but i am not sure how.

I have gotten this far:

[itex]\frac{d\chi ^2}{dFo} = -2\sum \frac{(di - bi - Fo)}{\sigma i^2}[/itex] = 0

any help is appreciated thanks

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Minimum chi squared estimation

Can you offer guidance or do you also need help?

Draft saved
Draft deleted

**Physics Forums | Science Articles, Homework Help, Discussion**