Tagged Questions
2
votes
2answers
161 views
Model selection with nonlinear fitting? Statistical tests seem ambiguous
I'm working on fitting an exponential model
$\mathrm{Flux} = A+Bt+F\left(\exp(t_0-t/T_r) + \exp(t-t_0/T_f)\right)^{-1}+...$
to astronomical data (a light curve).
$A$, $B$, $F$, $t_0$, $T_r$, and ...
6
votes
1answer
144 views
Residual, linear least squares and quality engineering
I wanted to ask this question on stackoverflow but I think it is more suitable here. If I am wrong, please tell me.
My question concerns the use in statistics to analyse physical/engineering data. As ...
5
votes
1answer
443 views
How to read the the goodness of fit on nls of R?
I am trying to interpreting the output of nls(). I have read this post but I still don't understand how to choose the best fit. From my fits I have two outputs:
...
3
votes
1answer
300 views
Pseudo-$R^2$: what are the null models for linear and non-linear regressions?
I have data from an experiment. The independent variable is time, the dependent variable is mass loss of organic matter. Now I want to compare whether a linear or a non-linear model fits better. From ...
0
votes
0answers
362 views
Log-normal distribution versus chi-square distribution for comparing RMSE of nonlinear fits
I have parameter estimates fitting a particular nonlinear model for thousands of experimental cycles. My goal is to find a nice way to tag those cycles which didn't fit the model very well. Currently ...
6
votes
3answers
1k views
How to assess goodness of fit of a particular nonlinear model? [closed]
I have a nonlinear model $y=\Phi(f(x,a)) + \varepsilon$, where $\Phi$ is the cdf of the standard normal distribution and f is nonlinear (see below). I want to test the goodness of fit of this model ...
