Huge Confidence Interval With predint

조회 수: 6 (최근 30일)
Samuel Salander
Samuel Salander 2021년 3월 24일
답변: Aditya Patil 2021년 3월 31일
I'm running into a confidence interval on a fit of some data. This is the code I'm using:
x0 = [1 1 1];
fitfun = fittype( @(a,b,c,x) a*x.^b+c)
[fitted_curve,gof] = fit(x,y,fitfun,'StartPoint',x0,'Weight', w, 'Lower', [0,-3,0],'Upper',[1000,0,1])
coeffvals = coeffvalues(fitted_curve);
p = predint(fitted_curve,x,0.001,'Observation','off');
Where w is calculated from inverse cube weighting:
The fit works well for this very small confidence interval (.1 % for .001). When I try to make a more meaningful fit and use 95% confidence, I get this:
Is there a way I can get a closer result for this 95% interval? predint must use "Observation" and "off" (changing to "functional" makes interval smaller, but it's not what I'm looking for).
Thanks so much for your help.

답변 (1개)

Aditya Patil
Aditya Patil 2021년 3월 31일
As per my understanding, you want to get a fit with lower confidence interval.
For this, you need to do one or more of the following,
  1. Modify data. Add new data, remove outliers, and converting between data representations
  2. Change fit function. Use a function with more degrees.
  3. Remove upper and lower limits on the coefficients.

카테고리

Help CenterFile Exchange에서 Linear and Nonlinear Regression에 대해 자세히 알아보기

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by