Hello,

In this answer, @bgoodri taught me that the scale parameter in `rstanarm::stan_lmer`

, to which we assign a Gamma prior with the help of `prior_covariance = decov(......)`

, corresponds to the between standard deviation in the case of a one-way ANOVA model with a random factor (`y ~ (1|factor)`

).

But what is this parameter for a general Gaussian linear mixed model? For example a two-way ANOVA (with/without interaction). And how to control the prior distribution on the group-levels variance components if there are multiple ones?