Sample fixed effect coefficients in a Random Intercept model
betaBlock.fRI(Omega, Y, X, Z, p, A, N)current covariance matrix
current outcome vector (Y.I=cos(theta)*R, Y.II=sin(theta)*R)
design matrix model parameters (differs per person)
design matrix for random effects (differs per person)
dimension X (number of columns/variables+indicator variables)
prior variance of fixed effect coefficients
sample size at second level