Re: [R] statistical test for comparison of two classifications (nominal)

2010-11-17 Thread Mattia Prosperi
the best partition among a set of candidate ones. Mattia Prosperi. 2010/11/17 Marc Schwartz marc_schwa...@me.com: On Nov 17, 2010, at 7:33 AM, Martin Tomko wrote: Dear all, I am having a hard time to figure out a suitable test for the match between two nominal classifications of the same set

Re: [R] predict.coxph and predict.survreg

2010-11-11 Thread Mattia Prosperi
Indeed, from the predict() function of the coxph you cannot get directly time predictions, but only linear and exponential risk scores. This is because, in order to get the time, a baseline hazard has to be computed and it is not straightforward since it is implicit in the Cox model. 2010/11/11

Re: [R] randomForest can not handle categorical predictors with more than 32 categories

2010-11-10 Thread Mattia Prosperi
try to transform the attributes that have more than 32 levels into dummy binary variables. 2010/11/10 Mai Dang mdmin...@gmail.com: I received this error Error in randomForest.default(m, y, ...) : Can not handle categorical predictors with more than 32 categories. using below code

[R] multi-level cox ph with time-dependent covariates

2010-11-03 Thread Mattia Prosperi
Dear all, I would like to know if it is possible to fit in R a Cox ph model with time-dependent covariates and to account for hierarchical effects at the same time. Additionally, I'd like also to know if it would be possible to perform any feature selection on this model fit. I have a data set

[R] multi-level cox ph with time-dependent covariates

2010-11-02 Thread Mattia Prosperi
Dear all, I would like to know if it is possible to fit in R a Cox ph model with time-dependent covariates and to account for hierarchical effects at the same time. Additionally, I'd like also to know if it would be possible to perform any feature selection on this model fit. I have a data set