stan-dev / stan

Stan development repository. The master branch contains the current release. The develop branch contains the latest stable development. See the Developer Process Wiki for details.
https://mc-stan.org
BSD 3-Clause "New" or "Revised" License
2.61k stars 369 forks source link

Typo on wiki: prior choice recommendation for correlation #3235

Closed MPRdthal closed 1 year ago

MPRdthal commented 1 year ago

Summary:

The wiki for prior choice recommendation has a typo in the boundary-avoiding prior section for a correlation parameter.

Description:

The line reads "For a correlation parameter, a Beta(2,2) parameter on 2*(rho - 1/2) will keep the point estimate [...]" a) the second instance of "parameter" should instead be "prior" b) this line uses the inverse of the transformation rather than the transformation itself

Instead I believe the line should read: "For a correlation parameter, a Beta(2,2) prior on rho/2 + 1/2 will keep the point estimate [...]" or "For a correlation parameter, a 2*(Beta(2,2)-1/2) prior on rho will keep the point estimate [...]"

bob-carpenter commented 1 year ago

Thanks for filing. Can you edit the wiki? And yes, that's should be f(x) = (x + 1)/2 to map (-1, 1) to (0, 1).

bob-carpenter commented 1 year ago

I just went ahead and made the change. Thanks again.