BPA/Ch.07 update

[ito4303]

I updated the models in Ch.07 of BPA. Would you review the code?

[bob-carpenter]

I just realized you could simplify some of this code.

psi = inv_logit(...);
z ~ bernoulli(psi);

is equivalent to

logit_psi = ...;
z ~ bernoulli_logit(logit_psi);

We have Bernoulli that takes a parameter on the logit scale, so you don't need an explicit inv_logit. I should update the manual!

[ito4303]

Thank you for reviewing the code. I'd like to repost the updated models after checking in Stan 2.13 or later.

[ito4303]

I have updated the models and checked using Stan 2.14. For consistency, bernoulli() is left unchanged.

[bob-carpenter]

Let me know if there's anything else you want me to look at. Otherwise, you can just go ahead and merge (or I can if you'd rather).

[ito4303]

Thank you for reviewing. I have no more changes in this chapter. Please merge the updates if they look good.