[R-sig-ME] lme4: Parameter contrasts?

[Steven J. Pierce]

You might want to check out whether the multcomp package would handle this. Bretz et al. (2010) describes use of the package. 

Bretz, F., Hothorn, T., & Westfall, P. (2010). Multiple comparisons using R. Boca Raton, FL: Chapman & Hall/CRC.


Steven J. Pierce, Ph.D.
Associate Director
Center for Statistical Training & Consulting (CSTAT)
Michigan State University

-----Original Message-----
From: Carpenter, Tom [mailto:tcarpenter at spu.edu] 
Sent: Wednesday, February 04, 2015 8:25 PM
To: r-sig-mixed-models at r-project.org
Subject: [R-sig-ME] lme4: Parameter contrasts?

Hoping someone has some advice here. I recently made the switch from using HLM to lmer. I know that in HLM, you could do a parameter contrast (e.g., contrast two fixed effects against each other and test the significance of the contrast). I was curious if anyone knows how to do this in R? I have run a model in lmer (with standardized predictors) and wish to see if one fixed effect is significantly larger (more predictive) than other fixed effect.

If that is not possible in lme4, does anyone have any advice for how to bootstrap it? I�m fine letting the thing run overnight to get a 95% CI if anyone has any suggestions.

Tom Carpenter, Ph.D.
Instructor of Psychology
Seattle Pacific University
3307 3rd Ave W. Suite 107,
Seattle, WA, 98119
tcarpenter at spu.edu<mailto:tcarpenter at spu.edu>
Office: (206) 281-2916
Fax: (206) 281-2695












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