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Hi everyone! I'm trying to teach myself R in order to do some data analysis. I'm a mathematics student and (only) familiar with matlab and latex. I'm working trough the "official" introduction to R at the moment, while simultaneously solving some exercises I found in the web. Before I post my (probably stupid) question, I'd like to ask you for some general advice. How do

NB: Not reply needed (Ben was extremely helpful!) I've just started using R last week and am still scratching my head. I have a data set and want to run a separate regression across each level of a factor (treating each one separately). The data right now is arranged such that the value of the factor along which I want to "split" my data is one column among many. Best way to do