Go Premium for a chance to win a PS4. Enter to Win

x
?
Solved

Fitting curves to curved decay rate and comparison thereof in minitab

Posted on 2004-08-03
6
Medium Priority
?
713 Views
Last Modified: 2013-11-13
Hi Folks,

Can anyone explain how to do the following in Minitab:

Want to fit a curve to a curved decay rate and then compare curves with something like analysis of covarience to see if them are the same or significantly different. Thought the curve would be an exponential decay but appears to be more cubic decay.

Lots of points on this one because I haven't a clue either about the answer or the question ;0)

Thanks,

Jes
0
Comment
Question by:SoggyP
  • 3
  • 2
6 Comments
 
LVL 27

Accepted Solution

by:
d-glitch earned 500 total points
ID: 11704869
I don't have or know MINITAB.  But MS Excel has lots of curve fitting and statistical functions, including covariance (COVAR).

Can you post the data so we can cee it??
0
 

Author Comment

by:SoggyP
ID: 11704932
Hi Folks,

@d-glitch: Sorry, I can't post the data as it's for my wifes Phd (and she'd probably kick my butt if I did) and also for some reason minitab is the tool of choice so other application options aren't, um, options ;0)

Thanks for trying.

Later,

Jes
0
 
LVL 27

Assisted Solution

by:aburr
aburr earned 500 total points
ID: 11712271
I am not familiar with minitab, but can make some comments on the curve fitting problem which may help you define the problem better.
I presume that by cubic decay you mean a curve like
y = A/(x^3)
and by exponential decay you mean a curve like
z = Ce^(Bx) and that you have a bunch of data points to which you want to fit the above curves and then compare the fit.

By the proper (usually least squares) method you can get values of A, B, and C. You will find that both curves look very similar (if the domain of x is reasonably small). If the theory suggests one or the other take that one.. If there is no theory, take the one with the least sum of the squares of the difference. If there is no theory perhaps some other curve would fit even better. In fact there is guarenteed to be a better curve.
0
Concerto's Cloud Advisory Services

Want to avoid the missteps to gaining all the benefits of the cloud? Learn more about the different assessment options from our Cloud Advisory team.

 
LVL 27

Expert Comment

by:d-glitch
ID: 11720003
Minitab has  online help and FAQ's.  It may help.  Here is the link:            http://www.minitab.com/support/answers/

I understand that you can't post preliminary, propriatary data.  

But could you post similar dummy data, or at least describe you real data?

For example:     20 sets of data.  Each set consists of 50 measurements of [population, concentration, temperature...] versus time.
0
 
LVL 27

Expert Comment

by:d-glitch
ID: 11720506
Minitab also has  online tutorials that may cover the topics you need:       http://www.minitab.com/resources/tutorials/
0
 

Author Comment

by:SoggyP
ID: 11724150
Hi Folks,

Well, my wife being a smartie (she'd have to be to understand all of the above) finally figured it out herself.  But you guys tried to help, so have some points.

Later,

Jes
0

Featured Post

Concerto Cloud for Software Providers & ISVs

Can Concerto Cloud Services help you focus on evolving your application offerings, while delivering the best cloud experience to your customers? From DevOps to revenue models and customer support, the answer is yes!

Learn how Concerto can help you.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Introduction This article explores the design of a cache system that can improve the performance of a web site or web application.  The assumption is that the web site has many more “read” operations than “write” operations (this is commonly the ca…
Lithium-ion batteries area cornerstone of today's portable electronic devices, and even though they are relied upon heavily, their chemistry and origin are not of common knowledge. This article is about a device on which every smartphone, laptop, an…
Although Jacob Bernoulli (1654-1705) has been credited as the creator of "Binomial Distribution Table", Gottfried Leibniz (1646-1716) did his dissertation on the subject in 1666; Leibniz you may recall is the co-inventor of "Calculus" and beat Isaac…
Finds all prime numbers in a range requested and places them in a public primes() array. I've demostrated a template size of 30 (2 * 3 * 5) but larger templates can be built such 210  (2 * 3 * 5 * 7) or 2310  (2 * 3 * 5 * 7 * 11). The larger templa…
Suggested Courses

886 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question