I have a zero-inflated y-variable.
Could you please confirm that my solutions for converting brms hurdle lognormal posterior values into meaningful estimates as y-variable units (lognormal part) or zero probabilities (hurdle part).
Model
model = brm(br(y ~ (1 | county), hu ~ (1 | county), data = data, family = hurdle_lognormal())
Posterior variables
get_variables(model)
[1] "b_Intercept"
[2] "b_hu_Intercept"
[3] "sd_county__Intercept"
[4] "sd_county__hu_Intercept"
[5] "sigma"
[6] "r_county[A,Intercept]"
[7] "r_county[B,Intercept]"
[8] "r_county[C,Intercept]"
[9] "r_county[D,Intercept]"
[10] "r_county__hu[A,Intercept]"
[11] "r_county__hu[B,Intercept]"
[12] "r_county__hu[C,Intercept]"
[13] "r_county__hu[D,Intercept]"
[14] "lp__"
[15] "accept_stat__"
[16] "stepsize__"
[17] "treedepth__"
[18] "n_leapfrog__"
[19] "divergent__"
[20] "energy__"
Solution for calculating mean y value for each county
I have to add "b_Intercept" and "r_county[ ,Intercept]", and take exp() of that? In code:
model %>%
spread_draws(b_Intercept, r_county[county,]) %>%
median_qi(condition_mean = exp(b_Intercept + r_county))
Solution for calculating zero probability (y = 0) for each county
I have to add "b_hu__Intercept" and "r_county__hu[ ,Intercept]", and put it into inv_logit_scaled() function? In code:
m %>%
spread_draws(b_hu_Intercept, r_county__hu[county,]) %>%
median_qi(condition_mean = inv_logit_scaled(b_hu_Intercept + r_county__hu))