Open zmbc opened 1 month ago
@zmbc I've never understood what x_min
and x_max
were for -- could you explain further? Also, I don't understand what exactly your example is showing, except that it seems like the CDF at a value we're calling "x min" shouldn't be as high as 67% or even 5%. But as I said, I don't know what x_min
and x_max
are actually for, so I don't know what this means.
it seems like the CDF at a value we're calling "x min" shouldn't be as high as 67% or even 5%
Yep that's it!
x_min
and x_max
are supposed to represent the support of the distribution in some numerical, computable sense. They have additional effects on mirrored distributions, which are what those notes and notebooks are about. In the case of mirrored distributions, it is important to match GBD, so the auto-generated x_min
and x_max
from this package should be used with caution!
They are approximated using a normal distribution
Do you mean lognormal?
Oops, yes!
My understanding is that
x_min
andx_max
, for the non-mirrored distributions, act only as "guardrails" against trying to compute something that we don't have precision to compute. They are approximated using a lognormal distribution, but this approximation can be quite bad. Then the "guardrails" become far too restrictive and prevent the user from computing something that they can totally compute with their precision.MCVE: