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...he first column is the dependent variable and all the rest are explanatory variables. The column names are in the first line of the file. But it seems lm() requires I know the variable names in advance? Is there a way to dynamically read in variable names and send to lm()? Many many thanks!!! Urania [[alternative HTML version deleted]]

In the logistic regression model, there is no residual log (pi/(1-pi)) = beta_0 + beta_1*X_1 + ..... But glm model will return residuals What is that? How to understand this? Can we put some residual in the logistic regression model by replacing pi with pi' (the estimated pi)? log (pi'/(1-pi')) = beta_0 + beta_1*X_1 + .....+ ei Thanks! [[alternative HTML version deleted]]

Hi, All: I only have 4 samples. I wish to get a confidence interval around the mean. Is it reasonable? If not, is there a way to compute a confidence interval for such small sample size's mean? Many thanks, U [[alternative HTML version deleted]]

I have a dataset of 10000 records which I want to use to compare two prediction models. I split the records into test dataset (size = ntest) and training dataset (size = ntrain). Then I run the two models. Now I want to shuffle the data and rerun the models. I want many shuffles. I know that the following command sample ((1:10000), ntrain) can pick ntrain numbers from 1 to 10000. Then I just