[R-sig-ME] Normal data vs normal residuals

[Célia Sofia Moreira]

I have the following two questions:

1) one of my variables, say y, is normally distributed (shapiro/lilliefors
tests). However, the residuals of
lmer(y ~ x + (1|Subject))
are not normally distributed. Thus, as far as I understand, I can not use
lmer results. I was thinking about replacing lmer by (robust) rlmer. Do you
agree? Is there a better recommended approach?

2) another variable, say z, is not normally distributed but the residuals of
lmer (z ~ x + (1|Subject))
pass the normality tests. May I accept the results of lmer?

Kind regards,
CSM

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