fit

1. Comparing fit of GLM to OLS regression

Hello talkstat. First post in this magnificent forum! In my master thesis I'm estimating health care expenses to patients, who has experienced a occupational injure on administrative data. The depended variable is total health care expenses for a given individual a year after the...
2. Non-linear model fit

Hi everyone. I am working on fitting a non-linear least squares model with R. My data points are virus contentration (ydata) over a timeline of 33 days (xdata). The decrease in virus concentration should be modeled with the following function: log(c/c0) = (-lambda0/alpha)*(exp(-alpha*time)-1)...
3. finding the best fit and removing outliers with MARS regression

I using the regression method called MARS, in R is it called earth and is located in the package earth, in order to find the best regression model for my datat. I know that this method is suitable for large data-sets, can handle NA and also decides which variables will be used and...
4. Errors on fit parameters with no errors on data

Hi all Many, maybe all, statistical packages I know of (R, matlab, root, sas) will allow you to fit data with no associated errors, and give you back fit paramters with errors. How is that possible? Many fit libraries use some form of maximum likelihood, e.g. minimizes chi squared or least...
5. How well a few values fit a given distribution?

Dear all, I have approximated two one-dimensional random variables A and B using Gaussian Mixture Models (3 gaussians). I used gmdistribution.fit Matlab function with 10000 values. The resulting distributions are called f_{A}(x) and f_{B}(x) (shown in attached Figure 1, being...