Chi-squared and reduced Chi-squared

  • Thread starter Liquidxlax
  • Start date
  • #1
Liquidxlax
322
0
In my physics honours lab to check our "goodness of fit" we have to use the Chi-squared and reduced Chi-squared equations.

For the Lab we use the text Bevington Data analysis and error reduction. I'm having a problem on determining whether or not my chi-squared values are good because the book states that chi-squared should be close to zero while the reduced chi-squared should be close to 1.

this obviously doesn't make sense because you divide chi-squared by the number of degrees of freedom which is a positive integer number.

Can somebody please explain to me the meaning of both reduced and chi-squared numbers?
 

Answers and Replies

  • #2
chiro
Science Advisor
4,815
134
In my physics honours lab to check our "goodness of fit" we have to use the Chi-squared and reduced Chi-squared equations.

For the Lab we use the text Bevington Data analysis and error reduction. I'm having a problem on determining whether or not my chi-squared values are good because the book states that chi-squared should be close to zero while the reduced chi-squared should be close to 1.

this obviously doesn't make sense because you divide chi-squared by the number of degrees of freedom which is a positive integer number.

Can somebody please explain to me the meaning of both reduced and chi-squared numbers?

I am not sure about the reduced chi-squared, but since you are measuring variation between expected and observed, it makes sense intuitively that the variation should be minimized (and hence close to zero).

Can you give the definition of a reduced chi-square distribution and any sample statistics that you have to calculate?
 

Suggested for: Chi-squared and reduced Chi-squared

  • Last Post
Replies
0
Views
737
Replies
1
Views
428
  • Last Post
Replies
1
Views
547
Replies
5
Views
555
Replies
5
Views
2K
Replies
5
Views
1K
Replies
8
Views
2K
Replies
6
Views
599
  • Last Post
Replies
8
Views
936
  • Last Post
Replies
17
Views
1K
Top