hello i have a mixed effect model which gives slope and intercept terms for 6 groups (diagnosis (3 levels) by risk group(2 levels)). the fixed part of the model is --
brain volume ~ Diagnosis + Risk Group + (Risk Group * age : Diagnosis) - 1 thus allowing risk group age/slope terms to vary within diagnosis and omitting a nonsignificant diagnosis by risk group intercept (age was centered) interaction. i am interested in whether differences in risk groups' developmental trajectories are different for different diagnoses. the last three (of 10) fixed effect estimates are estimates for the age/slope differences between risk groups for the 3 diagnostic groups. my question is this -- how do i test if the 3 differences are statistically different from each other? i can do this in SAS but the answer in R is eluding me. thanks in advance, dede ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
