[R] dealing with heteroscedasticity in lmer: problem with the method weights

ld I normalise the within group variance before implementing the model? And deal with the variance (as a new variable to explain) in another model? Is there another way to solve this problem? Thank you in advance for your help Doris Gomez [[alterna

[R] problems with contrast matrix

t initial par (65) What is/are the problems and the solutions? - Is the contrast matrix of a rank inferior to what it should be? - Are there some other code lines I should have put to facilitate convergence? Thank you for your help. Doris Gomez [[alternative HTML version de