Hi group, I have this type of data x(predictor), y(response), factor (grouping x into many groups, with 6-20 obs/group)
I want to fit a linear regression with one common intercept. 'factor' should only modify the slopes, not the intercept. The intercept is expected to be >0. If I use y~ x + factor, I get a different intercept for each factor level, but one slope only if I use y~ x * factor, I get the interaction term I want, but the intercept is not kept constant. Also, if I constrain teh intercept in the regression model (y~a+x*factor), I get estimates both for slope and intercept of each factor level. Robert ---------------------------------------------------------------------------------------------------------------------- NIVAs hovedkontor har flyttet til nye lokaler i CIENS - Forskningssenter for miljø og samfunn; Gaustadalléen 21, 0349 Oslo. Meld deg på vårt nyhetsbrev på www.niva.no ______________________________________________ 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.
