Hiya all, new to Stan here and I have a simple data-wrangling issue I’d like some advice on.
I’m aiming to run a mediation model from a simple repeated measures study, where x is the condition a given participant was in, m is a continuously measured mediator (measured only once), and y is a continuously measured DV measured at two time-points. Though it’s not necessarily tailored to 2-2-1 mediations, I was thinking I could still use bmlm–here’s a quick mock dataset of what the data would broadly look like:
And here’s the kind of basic model creation in bmlm I’m picturing at the moment
fit <- mlm(d = df, id = "id", x = "x", #??? m = "m", y = "y", iter = ... etc...)
The problem I’m seeing for use in bmlm is that x is multicategorical, not continuous, but I’m not sure how to specify that for bmlm purposes–any thoughts or ideas how to make a categorical x work in bmlm? Or is there perhaps an alternative way of going about this kind of model build?