Now, consider the case where our prior distribution is still \textsf{Beta}(a, b). Suppose we are to change our conditional likelihood model from \textsf{Ber}(p) to one of the options listed below, still maintaining the i.i.d. assumption for the observations. Which of these will necessarily result into the posterior distribution being a Beta distribution, regardless of the observations? Assume that we only define the likelihood over 0 \leq p \leq 1. (Choose all that apply.)

\textsf{Geom}(p)

\textsf{Poiss}(\frac{1}{p})

\textsf{Unif}([0, p])

\textsf{N}(0, p^2)

1 answer

The options that will necessarily result in the posterior distribution being a Beta distribution, regardless of the observations, are:

\textsf{Geom}(p)

\textsf{Unif}([0, p])