[R] AIC Methods

Benjamin Zuckerberg bzuckerb at syr.edu
Wed Sep 27 19:52:52 CEST 2006

I am having trouble with getting AIC statistics.  I have developed a  
number of ancova models using the lm function.  I am trying to get a  
number of AIC statistics suggested by Burnham and Anderson (2002)  
including raw AIC values, AICc values, Akaike weights, and Delta AIC.   
When I use the AIC function in (stats), I only get a single AIC value  
including degrees of freedom.  When I use the summary statement as  
suggested in the (aod) package, I do not get the resulting AIC  
statistics.  What am I doing wrong?  Is this a product of using the lm  
function for my models?  I have even investigated the use of  
extractAIC, but that does not provide me with the statistics I am  
looking for as well.  Do you have any suggestions?  In addition, I am  
also curious if there is a package or procedure for model averaging.

Thank you!

Benjamin Zuckerberg
Doctoral Candidate
State University of New York
College of Environmental Science and Forestry
Illick 244A, 1 Forestry Drive
Syracuse, New York 13210
Tele: (315) 470-6985
E-mail: bzuckerb at syr.edu

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