| T O P I C R E V I E W |
| Chirality899 |
Posted - 02/11/2013 : 1:45:13 PM
Origin Ver. and Service Release (Select Help-->About Origin): Origin 9.0 32 bit
Operating System: Windows 7
I was a bit confused on how if I can find my x intercept with standard error in Origin. I was able to calculating using x from y to find my intercept as well as the confidence intervals. I tried doing a web search and was unable to find any relevant information.
Is there a way to directly calculate this value ? |
| 2 L A T E S T R E P L I E S (Newest First) |
| Chirality899 |
Posted - 02/11/2013 : 4:34:04 PM
Thank you very much for the quick response. I was able to figure it out from your instructions |
| Hideo Fujii |
Posted - 02/11/2013 : 2:56:29 PM
Hi Chirality899,
Say, you have a linear fitting function: y=a+b*x , the x intercept (=x0) would be x0 = -(a/b),
which you can regard it as a derived parameter. Although you can calculate the
standard error of this derived parameter by the error propagation rule, maybe a convenient
and easy way may be that you define the above fit function with a derived parameter, x0
for the non-linear fitter. So,
1) Using Fitting Function Builder, define y=a+b*x with a derived parameter, x0=-(a/b) .
2) Run NLFit using this function. The report sheet shows the standard error of x0.
(See the screenshot below.)
Hope this helps.
--Hideo Fujii
OriginLab
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