Massimiliano Grassi

19 Questions 37 Answers 0 Followers

Questions related from Massimiliano Grassi

What is the correct way to calculate confidence intervals of an AUC obtained by merging/pooling predictions from different test sets?

I have one question regarding the CIs of the AUROC calculated merging/pooling the predictions coming from different test sets. In one analysis, we use a sort of nested cross-validation approach,...

09 September 2018 4,220 0 View

Is there a general and model-independent way of calculating prediction intervals in machine learning for regression task?

I’m training some supervised machine learning algorithm to perform the prediction of a continuous variable. I’m currently applying a nested cross-validation protocol (inner: LOOCV; outer: LOOCV;...

02 February 2018 8,872 5 View

Post-pre change or post scores in predicting treatment response give different cross-validated r-squared. Which should I consider?

I have trained a machine learning model to predict the outcome of a therapy based on some pretreatment information. Outcome is based on a questionnaire that is administered both before (pre) the...

02 February 2018 9,405 3 View

In cross-validation, which is the AUC population parameter I really want to estimate?

I’ve found a lot of different procedures to calculate the AUC confidence interval of a cross-validated model. it may sound quite theoretical but it is not clear to me which parameter these CI...

02 February 2017 6,054 7 View

Which Bootstrap for Confidence Interval of AUC with Leave-Pair-Out-Cross-Validation?

I have to calculate the CI of the AUC (Roc) for a series of classifiers (e.g. Lasso, Random Forest, SVM) learned using the same test dataset, in order to identify the best model for this problem...

12 December 2016 354 4 View

Topic analysis with rarely occurring topic and small document corpora. Which technique should I use?

Hi everyone, I need to perform a topic analysis on various corpora of documents and I need a procedure that can be applied to all of these corpora independently in a standard way. These are the...

10 October 2016 1,973 3 View

Recursive feature selection with cross-validation in the caret package (R): how is the final "best" feature set selected?

The rfe functions in the caret package allow to perform recursive feature selection (backward) with cross-validation. It is expected that the best features selected in each fold may differ, as...

09 September 2016 5,712 4 View

Does publication bias affect the meta-regression slope coefficient?

Hi everybody,differently than in meta-analyses, the effect of publication bias in meta-regression seems to me less severe for the slope coefficient, In my opinion, a bias in the slope coefficient...

05 May 2016 892 7 View

Power analysis in meta-regression?

Hi everyone,Is any package/code available to calculate power in meta-regression (random-effects, DL estimation)?None is available in R, as far as I know, but maybe it exists for another language...

05 May 2016 3,939 4 View

How is it correct to optimize a binary classifier output threshold with ROC and LPOCV?

Hello everyone and thank you in advance for you help! I'm building a screening tool with a machine learning algorithm. The model provides a probabilistic prediction (i.e. logistic regression,...

04 April 2016 4,446 7 View

Which Post-Hoc Strategy for a Poisson Repeated-Measure ANOVA?

Hi everyone and thank you for you advice.I'm running a two-way repeated-measure ANOVA, with two groups of subjects undergoing two different treatments (coded as: 0; 1) x 3 assessment times (coded...

08 August 2015 2,597 3 View

How can I calculate a multi-centric ICC (intra-class correlation) variation before and after an agreement training?

Hi and thank you to everybody. I have data regarding a training that aimed to improve the agreement among raters. Raters gave a dichotomous judgment (presence/absence).The study is multi-centric:...

06 June 2015 5,927 3 View

Is wild bootstrap valid in a “bordeline" case t-test?

I have to compare the mean levels of a continuos variable y (ranging 1-20) subdividing my sample in two groups according to a dichotomous variables (i.e gender). Sample sizes of the two groups are...

04 April 2015 5,099 5 View

Which is the Best Effect-Size for Predictors in Multivariate Logistic Regression?

We performed some analysis with multivariate logistic regression (several continuos independent variables and a single dichotomous dependent variable)A referee revising our paper asked us to show...

11 November 2014 9,275 9 View

What do you think is the most correct procedure for Socio-demographic covariates in regression models and neuropsychological tests?

The following is a recurrent issue in our study and by now no consensus have been reached in my team.   We made our subjects to perform some neuropsychological tests. An italian validation sample...

09 September 2014 1,500 4 View

Is it correct to use regression instead of meta-regression?

I’m trying to study if gender has a impact on the efficacy of a treatment. None of the studies available indicate the pre-post mean and sd split by gender, so a full meta-analytic approach is...

05 May 2014 8,728 6 View

MATLAB: Simultaneous analyses of multiple columns/variables?

I'm a beginner with Matlab so I'm sorry if this answer may sound silly to most of you who know MATLAB, but I'm stuck and cannot solve this matter. So thanks a lot in advance! I'm trying to...

02 February 2014 425 6 View

Intra-class correlation: any test to statistically compare its increase?

I have to compare two ICC calculated by the same three judges on the same sample of subjects (presence/absence of a certain physical dysfunction) after and before a training to improve the judges'...

02 February 2014 2,437 6 View

Does anyone have opinions about Parametric vs Non-Parametric Statistics?

When designs are not to complex and non-parametric approaches are easly applicable, I always run both of them even if assumptions of parametrical test are met. In my experience they both give...

02 February 2014 8,749 10 View