Dear all,
I have a very simple question but, have been having a hard time to figure
it out.
I am using a mixed model with random intercept and slope using lme function
with an unstructured covariance matrix. I know lmer uses Satterthwaite's
approximation method to approximate dfs of fixed effects, but I am not sure
what is the preferred method that lme uses. Is it Wald or Likelihood ratio?
I don't think lme offers such an option to specify an approximation method
for dfs of fixed effects. Does it?
I appreciate any response in advance.
Sala
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Salahadin (Sala) Lotfi
PhD Candidate of Cognitive Neuroscience
University of Wisconsin-Milwaukee
Anxiety Disorders Laboratory
President, Association of Clinical and Cognitive Neuroscience, UWM