Hello,

I want to estimate a 2-component mixture model for 3 ordinal variables that have 4, 7 and 6 categories. A priori, I think the two factors in the mixture will have Gaussian distributions.

Could you please tell me how to specify the priors for the analysis? My attempt to do this so far yields “Error: Expecting a single value when fixing parameters.”

The syntax that generates this error is:-

mix=mixture(gaussian,nmix=2)

prior=c(prior(cumulative(c(-1,0,1),threshold=‘flexible’)),

prior(cumulative(c(-3:2),threshold=‘flexible’)),

prior(cumulative(c(-3:1),threshold=‘flexible’)),

prior(dirichlet(2,2),theta))

j0=brm(bf(cbind(ordvar4,ordvar7,ordvar6)~1, dat, family=mix, prior=prior, inits=c(0,0,0)))

Ultimately, this is a multi-level problem. The ordvar ratings derive from human raters in about 2 dozen centers. So, I would like to generalise the final result to take center into account. I hope that adding +(1|center) to the formula will do this?

Thanks for your help

- Operating System: WIndows 10
- brms Version: 1.10.0