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confidence interval

AdditivePony307
Level I

How do I display a confidence interval in an exponential curve. I figured it out for a linear but not for an exponential curve. Thanks!

This post originally written in German and has been translated for your convenience. When you reply, it will also be translated back to German.

5 REPLIES 5
MRB3855
Super User

Re: confidence interval

Hi @AdditivePony307 : When you say "exponential" what exactly do you mean?

1. Something like this: Y=A*exp(k*x)

2. Something like this: Y = A*(1-exp(k*x))

 

If (1), then you can use Fit Y by X. Then choose "Fit Special..." and choose Natural Log under Y transformation (see screen shots below). If more like (2) the you will have to go through the non-linear platform. If (1) via below, then the "intercept" in the Parameter Estimates output is ln[A] (so A = exp[intercept] ) , and "X" (whatever your X is) is k.  

MRB3855_0-1713174986073.png

MRB3855_1-1713175002575.png

 

Re: confidence interval

Thanks for your reply!

My curve fit looks like this:

DOC(t) = DOC∞ + z0 -kt

it describes microbial drawdown of dissolved organic carbon (DOC) in water over time (t) in a bioassay.  This is part of a paper and the reviewer suggested to add the confidence area. Do you have an idea how? 

 

 

Re: confidence interval

Here is the correct formula:

DOC(t) = DOC∞ + z0 * exp(-kt)

MRB3855
Super User

Re: confidence interval

Hi @AdditivePony307 : OK, you will have to go through the Non Linear Platform; I'm assuming DOC-inf, z0, and k are parameters to be estimated via the regression. See this and come back if needed.

https://www.jmp.com/support/help/en/17.2/index.shtml#page/jmp/example-of-the-nonlinear-platform.shtm...

 

Re: confidence interval

Ok, thanks!