[FLR-list] Use of FLQuantPoint

[Mark Payne]

Ok, that makes sense, but I'm still a little unsure about how this should be implemented - as I understand it you're talking mainly about how to store the data, rather than pass it around. I currently have an array of accessor functions:

ssb(sam.object)
tsb(sam.object)
fbar(sam.object)
stock.n(sam.object)
harvest(sam.object)
rec(sam.object)

What sort of objects should these return, given that these quantites now can all have confidence intervals associated with them? 

Mark

________________________________________
Fra: flr-list-bounces at r-forge.wu-wien.ac.at [flr-list-bounces at r-forge.wu-wien.ac.at] På vegne af Laurie [lauriekell at googlemail.com]
Sendt: 8. oktober 2011 12:18
Til: flr-list at flr-project.org
Emne: Re: [FLR-list] Use of FLQuantPoint

On 10/08/2011 11:47 AM, Mark Payne wrote:
> Hi,
>
> I am a bit confused about the intended use of FLQuantPoints. The FLSAM assessment model returns the confidence intervals for nearly everything that it calculates, including, for example, the ssb. I am trying to write an accessor function that will return the ssb as an FLQuantPoint object. The problem is that the confidence intervals for this value are asymmetric, so it's not sufficient just to return the mean and the variance. I was wondering what the intention for the uppq and lowq dimension was? Is this the appropriate place to store the estimated confidence bounds? Or are they solely for cases where you have a large distribution that you are trying to characteriste non-parametrically ie through median and the quartiles...
>
> Second question - is there a plural class, FLQuantPoints? I can't seem to find one at the moment....
>
> Mark

You say ssb has an asymmetric distribution but that only matters  if it
is from an empirical distribution, e.g. derived from an MC simulation.
When I had a quick look at ssb, the upper & lower CIs were just +-1.96
times the CV. I.e. if you know the distribution and parameters you can
derive the CIs.
Also for what percentiles do you want the CIs? this will vary on a
case-by-case basis.

FLQuantPoint was designed to summarise the 6th dim (iter) to reduce
storage space. If you are not running MC simulations then there is no
need for FLQuantPoint.

Instead if you return the parameters and hessian as FLPar objects then
you can design methods to calculate quantities of interest.

Laurie


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