library(lme4)
fit1 <- lmer(Reaction ~ Days + (Days | Subject), sleepstudy)
re_var(fit1)
sleepstudy$mygrp <- sample(1:45, size = 180, replace = TRUE)
fit2 <- lmer(Reaction ~ Days + (1 | mygrp) + (Days | Subject), sleepstudy)
re_var(fit2)
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