I am trying to find correlations between multiple variables. To do so, I model them jointly from a multivariate normal (based on this). I placed LKJ(1) on the correlation matrix (to be unbiased)
vars <- colnames(dfcorradj)
form <- as.formula(
paste0("mvbind(", paste(vars, collapse = ","), ") ~ 1")
)
fit_corr <- brm(
data = dfcorradj,
formula = bf(form) + set_rescor(TRUE),
family = gaussian(),
sample_prior = "yes"
)
My question is, can I calculate the naive savage dickey ratio to test whether a correlation is zero? I wonder because if I set a correlation to zero, the derived marginals of the other correlations will change. But Savage–Dickey requires that the prior under (H_0) matches the conditional prior induced under (H_1) for the nuisance parameters, and I am having trouble understanding what the corresponding (H_0) prior would actually look like here.
Does the dependence between the correlations make naive savage dickey unsuitable, and if so, is there an alternate way?