1. S

    Nested vs non-nested model?

    Hi all, I am running a confirmatory factor analysis and trying to work out if my two models are nested or not - this will be important for me to decide how I compare the models (e.g. using just the AIC and CFI statistics to compare the two models, or whether I can also use the chi-square...
  2. C

    What technique to use?

    I am studying modeling, and I am looking for a good technique to optimize an insurance process, but I am not quite sure how to accomplish what I want to do. I have a dataset with several categorical variables (policy characteristics) and one numerical variable (historical losses). What I...
  3. G

    unconditional expectation for GARCH model with normal inovations

    Hi i have been asked to find unconditional expectations and then a recursive relation. I think I have started well but i am confused at how the recursive relation is made up. this is then to be used with a GARCH model i am working on. details of question: d(t) = mu + sigma(t)Z(t)...
  4. C

    how to determine what test to use for a project?

    I'm trying to determine if there is a statistical significance in hospital admission rates (asthma and bronchitis) before and after tobacco regulations went in to affect. I got the crude and adjusted rates with the 95% Confidence Intervals. Can I just use the 95%CIs to show statistical...
  5. D

    Binomial model with 'complete separation' ...?

    Hello All, I have a data set that is similar to this.. structure(list( = c(4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L), time2 = c(0, 0.30209836793605, 0.292033542976939, 0.00731537389688806, 0, 0, 0.0249544211485871, 0, 0.368636194723151...
  6. T

    Number of variables that can be included in an exact logistic regression

    I'm currently analyzing a dichotomous outcome using a small dataset of only 100 individuals. the outcome occurs in only 25 individuals and I have some predetermined confounders that I would like to adjust for. I know that I am limited by, at most, 2-3 variables if I were to model using a...
  7. S

    GAM with Gamma distribution-Default Inverse Link or Log-Link?

    solved. thank you!
  8. S

    Which method to compare models with truth?

    Hi all, Edit: First I must say sorry for the ridiculous spelling mistake in the title! I wish I could go back and change 'two' to 'to'. I have only just come across this forum while searching the net for some info - it looks fantastic so I'm hoping I'll get plenty of use out of it in the...