does cross validation work in r why does r use cross validation what is cross validation in r? how to cross validate models in r why is it useful to cross validate in r what is the role of cross validation what is cross validation in r what is cross validation in r why does it make sense to cross validation and predict? can r model and predict what is the cross validation used for in r cross validation of model for predicting what is an lda model when to cross validation models what is the difference between cross validation model and test model which model is cross validation how to use cross validation in r what is cross validation in r if model is cross validated does model prediction work why is it necessary to cross validate a model