I’m trying to model a process in which I observe a sum of two binomials:
y is observed,
N is known and I’m trying to infer
p_2 (I am aware that this isn’t “legitimate” Stan code, but I thought it’s a good way to describe the assumed data-generating process). I have informative priors for
p_2 (they should differ by an order of magnitude), and I hope this would help to deal with identifiability issues.
Is there any way to code something similar to this in Stan? Currently I’m using a poisson approximation to each, and then the sum is just another poisson… but I’m not sure this is a very good approximation here (both because
N is not very large, and because of possible correlations between them), and want to see if there’s “something better”.