Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Correlating data to a given curve

Correlating data to a given curve

Correlating data to a given curve

Has Excel a built in function to calculate the level of correlation between a set of data points and a given equation or other set of points?

Since the trendline function for the graphs will already give the correlation coefficient between a given set of data points and a best fit trend line generated by the program for these points.

Is there a way of using a different line to the trendline for the same calculation?

RE: Correlating data to a given curve

?You should be able to calculate it yourself, quite easily.  Recall the derivation of a least squares fit curve using calculus.  Just add up the square of the difference between each data point and what it "should be" (the other line or set of data points that you mentioned?) to get the sum of the square of errors and correlate from there?... it can be done manually once you have the definitions of what you are looking for.  I doubt is is built in .. however, defining what you need and programming it into Excel shouldnt be that tough?
Good luck...

RE: Correlating data to a given curve

One thing that should be carefully considered is potentially improper application of least squares regression.  

The basic premise is equal weighting of all errors.  This may lead to large errors if the data is highly non-linear or if there is a large dynamic range in the data.  Linearization prior to fitting may prove to be more useful.


RE: Correlating data to a given curve

try the CORREL function...

RE: Correlating data to a given curve

Thanks melone - that's exactly what I was looking for

It works in StarOffice anyway, that's all I have access to at the moment.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close