OK, great. The R package installation seemed to work now. However, when I evaluate the setup, I still get an error that R packages are not installed. That is weird, because the installation seemed to work smoothly. I tried to install each package separately (phia, afex and brms) and got a note for each package that it was successfully installed on the computer (and a few warning messages that seemed irrelevant). But the evaluation still insisted the R programs are not installed! Maybe there is a different way to evaluate the setup?
Thanks a lot.