Re: [R] Models with ordered and unordered factors

2011-11-16 Thread Catarina Miranda
Thanks a lot for your answers and reading suggestions, now I know my guess was completely wrong. I guess in my case it will be more informative to keep the unordered factors. That way I can know not only that days differ in general, but also get information on which day is differing from day 1.

[R] Models with ordered and unordered factors

2011-11-15 Thread Catarina Miranda
Hello; I am having a problems with the interpretation of models using ordered or unordered predictors. I am running models in lmer but I will try to give a simplified example data set using lm. Both in the example and in my real data set I use a predictor variable referring to 3 consecutive days

Re: [R] Models with ordered and unordered factors

2011-11-15 Thread Bert Gunter
Ordered factors use orthogonal polynomial contrasts by default. The .L and .Q stand for the linear and quadratic terms. Unordered factors use treatment contrasts although (they're actually not contrasts), that are interpreted as you described. If you do not know what this means, you need to do

Re: [R] Models with ordered and unordered factors

2011-11-15 Thread Bert Gunter
... In addition, the following may also be informative. f - paste(day, 1:3) contrasts(ordered(f)) .L .Q [1,] -7.071068e-01 0.4082483 [2,] -7.850462e-17 -0.8164966 [3,] 7.071068e-01 0.4082483 contrasts(factor(f)) day 2 day 3 day 1 0 0 day 2 1 0

Re: [R] Models with ordered and unordered factors

2011-11-15 Thread Paul Johnson
On Tue, Nov 15, 2011 at 9:00 AM, Catarina Miranda catarina.mira...@gmail.com wrote: Hello; I am having a problems with the interpretation of models using ordered or unordered predictors. I am running models in lmer but I will try to give a simplified example data set using lm. Both in the