search for: radaelli

Dear List, quantile(x) function allows to obtain specified quantiles of a vector of observations x. Is there an analogous function to compute quantiles in the case one have the vector of the observations x and the correspondent vector f of relative frequencies ? Thank you Paolo Radaelli [[alternative HTML version deleted]]

...itting index "Gini" are used. In particular I'd like to have look to the source code that works out the best split for un unordered predictor. Does anyone can suggest me which functions in the sources I should consider ? Any input would be highly appreciated. Thank you Paolo Paolo Radaelli Dipartimento di Metodi Quantitativi per le Scienze Economiche ed Aziendali Facolt? di Economia Universit? degli Studi di Milano-Bicocca Via Bicocca degli Arcimboldi, 8 20126 Milano Italy e-mail paolo.radaelli at unimib.it Tel +39 02 6448 3163 Fax +39 02 6448 3105

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...tinuous) { # continuous x variable temp <- cumsum(y*wt)[-n] left.wt <- cumsum(wt)[-n] right.wt <- sum(wt) - left.wt lmean <- temp/left.wt rmean <- -temp/right.wt goodness <- (left.wt*lmean^2 + right.wt*rmean^2)/sum(wt*y^2) list(goodness= goodness, direction=sign(lmean)) } } Paolo Radaelli Dipartimento di Metodi Quantitativi per le Scienze Economiche ed Aziendali Facolt? di Economia Universit? degli Studi di Milano-Bicocca P.zza dell'Ateneo Nuovo, 1 20126 Milano Italy e-mail paolo.radaelli a unimib.it

...s this mean that the observations are divided into 10 groups and, as before, the xerror is computed by averaging the erorrs one gets in predicting the class of a group of obs by the tree obtained with the others 9 ? xstd is the standard deviation of this errors ? Thank you for your help Paolo Radaelli Paolo Radaelli Dipartimento di Metodi Quantitativi per le Scienze Economiche ed Aziendali Facolt? di Economia Universit? degli Studi di Milano-Bicocca Via Bicocca degli Arcimboldi, 8 20126 Milano Italy e-mail paolo.radaelli at unimib.it Tel +39 02 6448 3163 Fax +39 02 6448 3105 begin included me...

...part.control it denotes the number of times that the cross-validation is performed. Am I right ? If so, how many subsets compose the learning sample when performing one of the xval cross-validations ? Is it a 10-fold cross-validation repeated xval=10 times ? Thank you for your help Paolo Paolo Radaelli Dipartimento di Metodi Quantitativi per le Scienze Economiche ed Aziendali Facolt? di Economia Universit? degli Studi di Milano-Bicocca Via Bicocca degli Arcimboldi, 8 20126 Milano Italy e-mail paolo.radaelli at unimib.it Tel +39 02 6448 3163 Fax +39 02 6448 3105

I've just installed R 1.0.8 (for Windows) and I tried to install the package Quantreg directly from Cran but it's not in the list of downlodable packages. I tried also downloading the zip file and then install it but there is an error. How can I do it? Thank you [[alternative HTML version deleted]]

Dear all, could you please suggest me the package I have to install in order to use ranks statistics in regression models (R-Estimators, wilcoxon scores ...) Thanks and Happy Easter Paolo Radaelli [[alternative HTML version deleted]]

Dear R users, I'm using the rpart package to build classification trees. I'm interested in implementing the ordered Twoing as a splitting criterion. Does anyone have experience with this task ? Thank you for your help Paolo Paolo Radaelli Dipartimento di Metodi Quantitativi per le Scienze Economiche ed Aziendali Facolt? di Economia Universit? degli Studi di Milano-Bicocca Via Bicocca degli Arcimboldi, 8 20126 Milano Italy e-mail paolo.radaelli at unimib.it Tel +39 02 6448 3163 Fax +39 02 6448 3105

...the source code of the functions rpart.s and rpart.class.s but it is quite hard for me to understand which part of the code I should include in definining my own eval and init functions. Does anyone can suggest me how to proceed ? Any input would be highly appreciated. > Thank you Paolo Paolo Radaelli Dipartimento di Metodi Quantitativi per le Scienze Economiche ed Aziendali Facolt? di Economia Universit? degli Studi di Milano-Bicocca Via Bicocca degli Arcimboldi, 8 20126 Milano Italy e-mail paolo.radaelli at unimib.it Tel +39 02 6448 3163 Fax +39 02 6448 3105

Dear everybody! In the function hclust, at each stage distances between clusters are recomputed by the Lance-Williams dissimilarity update formula according to the particular clustering method being used. Using "centroid" method, Lance-Williams recurrence formula works properly only for euclidean distance. How is it possible to use properly centroid method with manhattan distance ?