Re: [R-sig-eco] AIC in R: back-transforming standardized model parameters (slopes)

2016-01-12 Thread Matt Perkins
Hi Drew and R-help, Many thanks for your email, and your explanations and suggestions have been very helpful in aiding me to understand this problem. Should you, or anyone else on the helplist have time, perhaps I may elaborate on my problem with a little more detail. I appreciate the

[R-sig-eco] Back transforming standardized model parameters when there is an interaction

2016-01-12 Thread Dixon, Philip M [STAT]
Matt, The interaction term is why the usual transformation doesn't work, at least initially. The R parameterization of factor effects makes it easy to fall into the trap of thinking that the coefficient for a main effect "means" something when there is an interaction in the model. Sometimes

Re: [R-sig-eco] AIC in R: back-transforming standardized model parameters (slopes)

2016-01-12 Thread Bob O'Hara
On 12/01/16 10:54, Matt Perkins wrote: Hi Drew and R-help, Many thanks for your email, and your explanations and suggestions have been very helpful in aiding me to understand this problem. Should you, or anyone else on the helplist have time, perhaps I may elaborate on my problem with a

Re: [R-sig-eco] AIC in R: back-transforming standardized model parameters (slopes)

2016-01-12 Thread Cade, Brian
Just to echo Bob O'Hara's comment and elaborate a bit more - Don't model average the regression coefficients, especially if you are considering models with and without interactions among the predictors. Follow the link provided by Bob to Cade (2015. Model averaging and muddled multimodel