I have model-data named as: model that is split as model.T(train) and model.V(test or validation). The least square model (from lm to step) is built withmodel.T and I like to see how model.T is robust by comparing predicted model.V toactual model.V. How do I get score for model.V based on model built on model.T? The code highlighted below does not get what I expected.Please advise! Thanks! ? # score the model ? score.T <- data.frame(predict(step, model.T))? # get predicted score for train data ? score.V <- data.frame(predict(step, model.V))? # for test data but seems incorrect ? # get the actual values ? actual.T <- data.frame(model.T$sales) ? actual.V <- data.frame(model.V$sales) ? # comparison for model.T ? comp.T=cbind(actual.T,round(score.T,digit=2)) ? plot(comp.T)? # comparison for model.V (use Model.T to predict Model.V for true validation ? comp.V=cbind(actual.V,round(score.V,digit=2)) ? plot(comp.V) [[alternative HTML version deleted]]