Giuseppe Biondi Zoccai
2005-May-07 17:52 UTC
[R] help for bootstrap of backward stepwise logistic regression
I would like to perform a bootstrap validation of a backward stepwise logistic regression analysis, but I am a beginner with R and I am not sure of how to do it. Is there anyone that can send me a sample file in tab format (that I can modify in Excel by pasting my data) and the pertinent R algorithm? Many thanks Giuseppe -- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Dr. Giuseppe Biondi Zoccai Interventional Cardiology Unit St Raffaele Hospital via Olgettina 60 20132 Milan ITALY Phone: +39-3408626829 Fax: +39-0226437339 Email: gbiondizoccai at gmail.com ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Frank E Harrell Jr
2005-May-07 22:31 UTC
[R] help for bootstrap of backward stepwise logistic regression
Giuseppe Biondi Zoccai wrote:> I would like to perform a bootstrap validation of a backward stepwise > logistic regression analysis, but I am a beginner with R and I am not > sure of how to do it. > Is there anyone that can send me a sample file in tab format (that I > can modify in Excel by pasting my data) and the pertinent R algorithm? > Many thanks > Giuseppe >You are asking for a lot and not saying that you are willing to read background material or help files. To get you started, install the Design and Hmisc packages and look at help files for the following in Design: fastbw, lrm, validate.lrm, calibrate.lrm Frank -- Frank E Harrell Jr Professor and Chair School of Medicine Department of Biostatistics Vanderbilt University