Dear all, I am trying to fit a multiple linear regression model to a table of data. My data.frame is like this ...
fit.data <- data.frame(y, x1, x2, x3, x4, x5, x6), then I use the linea regression command ... lm(formula = y ~ x1 + x2 + x3 + x4 + x5 + x6, data = fit.data) however, for some tables the data in column x1 is equal to -x2, so I get NA values for both coefficients of x1 and x2. I need to have real fitted coefficients for all the parameters or the physical meaning of the parameters is lost. Is there any way of forcing R to fit all the parameters? I have seen the contrast option but I don't really understand it (I am not a statistician) so I would be greatful if anyone could explain that. Kind Regards Chibisi [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.