[R] SEM interaction
adick at uchicago.edu
Tue May 25 17:38:24 CEST 2010
This is a general stats question--I realize it is an R help list, so
tell me to go away if it is inappropriate.
I have a 2 X 2 design, and I have specified four identical path models
(one for each level of each factor). I want to test for an interaction
at each path--essentially (A1 - A2) - (B1 - B2) != 0. I was thinking of
computing a contrast for each path of interest, such that I compute the
difference of the difference in the (non-standardized) path weights (as
above), and then divide this by the pooled standard errors of the
estimates (average of the standard errors).
Does this seem statistically sound, or am I way off base? I typically
compare path weights across two levels (e.g., age differences in a path
weight for the same theoretical model) using the stacked model approach,
but am not sure how to apply this to the interaction.
Anthony Steven Dick, Ph.D.
Human Neuroscience Laboratory
Department of Neurology
The University of Chicago
5841 S. Maryland Ave. MC-2030
Chicago, IL 60637
Email: adick at uchicago.edu
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