Dear community, I'm doing a lm. In the independent variables I've got a categorical one. Here is its histogram: http://r.789695.n4.nabble.com/file/n3333638/altitude.png I did this regression: lmeo2.52f <- lm(dat82$IncAltuDom ~ dat82$hdom2+log(dat82$CV)+ dat82$CA+ dat82$FCC+ factor(dat82$IdAltitud)) I obtain: Coefficients: Estimate Std. Error t value Pr(>|t|) (Intercept) 8.78222 0.94619 9.282 3.72e-15 *** dat82$hdom2 -0.30859 0.03875 -7.963 2.73e-12 *** log(dat82$CV) -0.42943 0.24568 -1.748 0.0835 . dat82$CA -2.98157 2.29904 -1.297 0.1977 dat82$FCC 0.02300 0.01067 2.156 0.0335 * factor(dat82$IdAltitud)1 -0.12142 0.40361 -0.301 0.7642 factor(dat82$IdAltitud)2 0.24341 0.43451 0.560 0.5766 factor(dat82$IdAltitud)3 -0.64904 0.47114 -1.378 0.1714 factor(dat82$IdAltitud)4 -1.14334 0.67509 -1.694 0.0935 . factor(dat82$IdAltitud)5 -2.13251 0.82463 -2.586 0.0112 * I thought I need to recodify my factor, q1 How can I do it? q2 Apologies I'm pretty newbie with this, ... I don't know how to interpret the regression when factors ... The factors created by default, compare the 1st factor with the other 5? ... but what does it mean??? is it good in my case ?? Thanks in advance, user at host.com -- View this message in context: http://r.789695.n4.nabble.com/Recodifying-a-factor-due-to-results-in-lm-tp3333638p3333638.html Sent from the R help mailing list archive at Nabble.com.