First pass at writing a novice lesson on going from prior and observed data to a posterior

[docsteveharris]

we start with a beta prior (e.g. 1/19 thing)
we observe a proportion of discharges
we assume a binomial model
we update our posterior give the above

can we both do this and teach it?

[docsteveharris]

zella first pass done and published
steve first pass partly done and not published