# andrea

PhD student.

 Jul 2 awarded Curious May 27 awarded Tumbleweed May 20 asked Poisson regression on partially missing covariates May 11 comment Can I trust a model if I do not check the prediction error?Related to Glen_b's comment: darden.virginia.edu/web/uploadedFiles/Darden/Faculty_Research/… Apr 25 comment Normalization of dummy variablesYou might find this paper by A. Gelman interesting stat.columbia.edu/~gelman/research/published/standardizing7.pdf Mar 12 comment Simulate predicted probabilities after a logistic regressionSee here: stata.com/support/faqs/statistics/… Feb 16 awarded Yearling Feb 16 awarded Yearling Jan 2 awarded Nice Answer Nov 11 awarded Commentator Nov 11 comment Why do so many people apply to so few PhD programs?PhD students are not chosen randomly from those who apply! Oct 10 comment SNP genotype coding in regressionIt should be the other way around. If you're assuming a gene-dosage effect you have only one parameter and it's a one degree of freedom test. If you dpn't assume the gene-dosage effect, you have 2 parameters and if you want to test them jointly it's a 2 dof test. Oct 5 comment Concerns about the size of odds-ratio estimates in binary logistic regression model\$\exp(0)=1\$ and not \$0\$ (in the last row, `[L1 Reading=0]`) Oct 2 awarded Yearling Sep 30 comment Difference between Maximum a posteriori and penalized likelihoodI don't know if this can be of any help, but - for example - quadratic loglikelihood penalization (squared \$L_2\$ norm) corresponds to having independent normal priors on the model parameters. I don't know the deatils of the paper you're referring to, but it's definitely not impossible to "exploit" PL for that purpose - Or maybe I've misunderstood your question? Sep 29 comment What statistical test is appropriate when comparing heart rates from different devices?Since apparently you (@phedonrousou) have repeated measures on the same subjects, this paper might prove useful: Myles & Cui, Using the Blandâ€“Altman method to measure agreement with repeated measures - British Journal of Anaesthesia 309â€“11 (2007), doi:10.1093/bja/aem214 Sep 26 comment Multiple imputation of time variables -- which step to impute?Before turning that comment into an answer... I was thinking, `t` is likely to be a censored r.v., right? I think this is a major issue when it comes to imputing `t` using, for example, MICE. But what about quantile imputation? Look for example at this: stata.com/meeting/sweden11/abstracts/bottai_nordic11.pdf if you don't have administrative truncation of the follow-up, this might be a solution. Imputation of missing values using laplace regression can take care of the fact that `t` is (most likely very skewed and) censored. @EpiGrad Sep 25 comment Multicollinearity and Splines :: Is there a problem?You can always orthogonalize the generated splines (for example the `rcsgen` Stata command uses Gram-Schmidt orthogonalizaton) Sep 23 awarded Constituent Sep 17 awarded Caucus