[R] fixed effects anova in lme lmer

Simon Blomberg s.blomberg1 at uq.edu.au
Wed Jun 6 04:23:43 CEST 2007


?gls in package nlme. It's like lme but with no random effects. But you
can still model the variance-covariance properties of the data.

Simon.

On Tue, 2007-06-05 at 19:11 -0700, toby909 at gmail.com wrote:
> Can lme or lmer fit a plain regular fixed effects anova? Ie a model without a 
> random effect, or have there be at least one random effect in order for these 
> functions to work?
> 
> Trying to run such, (1) without specifying a random effect produces an error, 
> (2) specifying that there is no random effect does not produce the same output 
> as  an anova run in lm(); (2b) specifying that there is no random effect in lmer 
> crashed R (division by zero, I think).
> 
> Just trying to see the connection of fixed and random effects anova in R. STATA 
> gives me same results for both models up to the point where they differ.
> 
> Best Toby
> 
> 
> 
> 
> 
> dt1 = 
> as.data.frame(cbind(c(28,35,27,21,21,36,25,18,26,38,27,17,16,25,22,18),c(1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4)))
> 
> summary(a1 <- lm(V1~factor(V2)-1, dt1))
> anova(a1)
> 
> summary(a1 <- lm(V1~factor(V2), dt1))
> anova(a1)
> 
> dt1$f = factor(dt1$V2)
> 
> summary(a2 <- lme(V1~f, dt1))   #1a
> 
> summary(a2 <- lme(V1~f, dt1, ~-1|f))   #2a
> anova(a2)
> 
> lmer(V1~f, dt1)   #1b
> 
> lmer(V1~f+(-1|f), dt1)   #2b
> 
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-- 
Simon Blomberg, BSc (Hons), PhD, MAppStat. 
Lecturer and Consultant Statistician 
Faculty of Biological and Chemical Sciences 
The University of Queensland 
St. Lucia Queensland 4072 
Australia

Room 320, Goddard Building (8)
T: +61 7 3365 2506 
email: S.Blomberg1_at_uq.edu.au 

The combination of some data and an aching desire for 
an answer does not ensure that a reasonable answer can 
be extracted from a given body of data. - John Tukey.



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