Produces a vcmm_summary object with a coefficient table for
the fixed-effects, the variance components, and basic fit
diagnostics. print() renders it in the style of lm /
lmer.
Details
The standard errors are the square roots of the diagonal of
vcov(object, which = "beta"), treating \(\sigma_\varepsilon\)
and \(\sigma_\alpha\) (or \(\Sigma_\alpha\)) as fixed at their
fitted values. They are first-order valid (Theorem 3.1) but do not
adjust for variance-component uncertainty.
For re_cov %in% c("kronecker", "separable"), the variance-
components block of the printed summary displays the estimated
\(\Sigma_{\mathrm{left}}\) (\(\Sigma_{2\times 2}\) for OD or
\(\Sigma_q\) for group-shared dense) instead of a scalar
\(\sigma_\alpha\).