Hello,

I am trying to fit a model where there is some effect of age and treatment.

Y_i = \alpha + \beta_1 \cdot \text{Age} + \beta_2 \cdot T

However, there is also a known selection bias. Those in my sample are not the same as the population as a whole.

I know how to calculate weights in a frequentist setting to reweight my population. But how do I do this with MrP? Is it possible to just add my cells like so:

Y_i = \alpha + \beta_1 \cdot \text{Age} + \beta_2 \cdot T + \alpha^{\text{ethnicity}}_{\text{ethnicity}[i]} + ...

Or, do I need to include a random effect for age and T at each cell?

The question is what is the effect of age and treatment at the population level? What should I do?

Thanks!