[R-sig-ME] Testing differences in measurement variance

[Mike Lawrence]

Hi folks,

Can mixed effects modelling be used to compare the variability of
measurement between treatments? That is, in the conventional ANOVA
world, if I were interested in studying the effect of a treatment
(within or between groups) on the variability of measurement, I would
(1) measure multiple individuals each multiple times, obtain an SD of
measurement per individual, then (2) submit these SD scores as a
dependent variable to an ANOVA. I wonder if this traditional two-stage
process could be replaced with a single mixed effects analysis, which
presumably would permit increased power through things like shrinkage,
accounting for measurement confidence (by taking into account
different numbers of observations within each individual), etc.

If this is possible, how would I structure the lmer() call to achieve
such estimation and comparison of measurement variance?

Mike

-- 
Mike Lawrence
Graduate Student
Department of Psychology
Dalhousie University

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~ Certainty is folly... I think. ~