[R-sig-ME] Make a 'between-and-within-factors' ANOVA with lmer function

[ian m s white]

I reckon lmer can figure out for itself what is between and what is within subjects, so

lmer(DV ~ IV1*IV2*IV3*IV4 + (1|Subject))

should fit the same model as your ANOVA.


On 24 Mar 2013, at 08:56, Vanni Rovera <vanni.rovera at gmail.com> wrote:

> Hi there,
> 
> I'm trying to understand how to use the function lmer in order to do a
> 'between-and-within-factors' ANOVA, but without any success. I know about
> the usage of the function aov, but this holds only for balanced designs;
> its documentation say to use lme function (package nlme) for unbalanced
> designs. Furthermore I found the lmer function (package lme4) is an
> evolution of lme, so I wish to use this last function in order to perform
> my ANOVA. But I'm not able to understand how to do this.
> 
> More precisely, imagine you have a dependent variable DV and four
> independent variables IV1, IV2, IV3, IV4, where IV1, IV2 are
> between-factors and IV3, IV4 are within-factors. Moreover you have a
> variable called Subject in order to identify the subject on which
> measurements are done (like for example this dataset:
> http://personality-project.org/r/datasets/R.appendix5.data). If I use the
> aov function, my 'between-and-within-factors' ANOVA would stand as follows:
> 
> aov(DV~(IV1*IV2*IV3*IV4)+Error(Subject/(IV3*IV4))).
> 
> Now can you write me the precise syntax in order to obtain the same result
> with the lmer function?
> 
> Thanks a lot in advance!
> Vanni Rovera
> 
> 
> 
> *Additional details:* The problem is that no one seems to be interested in
> explain the relations of 'within-factor' and 'between-factor' concepts with
> those of 'fixed-effect' and 'random-effect'. Textbooks and papers about
> ANOVA talk about between and within factors, while documentations and
> papers about lmer function talk about mixed-effects models, i.e. they talk
> about fixed and random effects, without mentioning between and within
> factors. *Thus I am not able to understand the relations between the two,
> since I think they are completely uncorrelated each others, and hence I am
> not able to use the syntax in lmer in order to distinguish between factors
> from within factors.*
> 
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> 
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