Displaying 1 result from an estimated 1 matches for "delspdwos".
2005 Jun 29
1
poly() in lm() leads to wrong coefficients (but correct residuals)
Dear all,
I am using poly() in lm() in the following form.
1> DelsDPWOS.lm3 <- lm(DelsPDWOS[,1] ~ poly(DelsPDWOS[,4],3))
2> DelsDPWOS.I.lm3 <- lm(DelsPDWOS[,1] ~ poly(I(DelsPDWOS[,4]),3))
3> DelsDPWOS.2.lm3 <-
lm(DelsPDWOS[,1]~DelsPDWOS[,4]+I(DelsPDWOS[,4]^2)+I(DelsPDWOS[,4]^3))
1 and 2 lead to identical but wrong results. 3 is correct. Surprisingly
(to me) the residuals...