The Origin Forum
File Exchange
Try Origin for Free
The Origin Forum
Home | Profile | Register | Active Topics | Members | Search | FAQ | Send File to Tech support
Username:
 Password:
Save Password
Forgot your Password? | Admin Options

 All Forums
 Origin Forum
 Origin Forum
 straight line data with errors in both coordinates		  New Topic  Reply to Topic
 Printer Friendly
Author Previous Topic Topic Next Topic Lock Topic Edit Topic Delete Topic New Topic Reply to Topic

judithsu

USA
Posts
Posted - 08/30/2005 :  6:56:13 PM  Show Profile  Edit Topic  Reply with Quote  View user's IP address  Delete Topic
Origin Version (Select Help-->About Origin): 6.0
Operating System: win xp
---------------

Hi, I'm interested in doing a linear regression (y = a + bx) to a set of data points accounting for the error in x and the error in y. I'm interested in the values of a and b, their uncertainity, and the chi-squared value. Does Origin already have this capability and if so how would I access it. Any help would be greatly appreciated. Thank you very much!

Mike Buess

USA
3037 Posts
Posted - 08/30/2005 :  9:38:08 PM  Show Profile  Edit Reply  Reply with Quote  View user's IP address  Delete Reply
There are several ways to fit to a straight line in Origin but I think you need the nonlinear curve fitter to get chi-sqr...

Help > Origin > Curve Fitting > The Nonlinear Least Squares Fitter

The line function is in the Polynomial fitting category which was disabled for some reason in Origin 6.0. To enable that category close Origin, find NLSF.ini in your Origin folder and open it in Notepad. In the [Category] section you will find the line

;Polynomial=fitfunc

Remove the semicolon (;) and save your changes. When you start Orign you will see a Polynomial category in the nonlinear curve fitter. Select that category and the Line function within.

...Just noticed that you wanted to take into account errors in X. That's not possible, the fitter will only handle errors in Y.

Mike Buess
Origin WebRing Member

Edited by - Mike Buess on 08/30/2005 10:32:26 PM
Go to Top of Page
  Previous Topic Topic Next Topic Lock Topic Edit Topic Delete Topic New Topic Reply to Topic
 New Topic  Reply to Topic
 Printer Friendly
Jump To:
The Origin Forum © 2020 Originlab Corporation Go To Top Of Page
Snitz Forums 2000