How do I make my Mixed model work with AR(1) covariance structure?
I have a large(2010X 4) data set and I need to calculate the effects of cycles and stresses on my wave speeds along with the interaction between them. My wavespeeds are collected for 4 stress levels so stresses here are repeated measurements. Here is a glimpse of what my stacked table looks like : N=subject on first row, CYC=cycle number on second row, STR: stress levels on third row and wave spee...