Make a 'between-and-within-factors' ANOVA with lmer function
On Mar 23, 2013, at 4:06 AM, Vanni Rovera wrote:
Hi there I don't know if this is the right place to do such a question, but nonetheless I try.
It is very much not the correct place to post this. There is no Mac-spcific content and there is a mixed-models mailing list wher ethis would be completely appropriate. You should do the necessary subscription and reading of their FAQ before re-posting. http://www.r-project.org/mail.html https://stat.ethz.ch/mailman/listinfo/r-sig-mixed-models http://glmm.wikidot.com/faq
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 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, and forgive me in the case this topic is inappropriate with this mailing list. *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 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. [[alternative HTML version deleted]]
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