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Re: [ddlm-group] Improving the enumeration_range definition.

Dear Group,

Apologies for 'necroposting', I'm trying to clear up some outstanding issues.  May I suggest the following definitional text for _enumeration.range to take into account Herbert's reasonable objections? I have avoided being prescriptive in how the likelihood of a given value outside the limits is calculated, instead attempting to communicate that the range is an ideal range.

(Old text)

      The inclusive range of values "from:to" allowed for the defined item.

(New text)

      The inclusive range of values "from:to" allowed for the defined item. If items have associated SU, the reported value may fall outside these limits.

On Fri, 28 Jun 2019 at 20:11, Herbert J. Bernstein <yayahjb@gmail.com> wrote:
Why 3 SU and not 6SU or 1 SU?  I don't mind specifying the probability distributions (in crystallography both Gaussian and Poisson statistics are important) and confidence intervals intended, but this needs more detail if it is to make statistical sense.   In the case of counting statistics we definitely should not mix the limits on the mean being specified with the sigma and in the case of crystallographic atomic coordinates the experiment tells us the means and the sigmas from which we could compute confidence intervals, but distorting any specified enumeration limits by some number of sigma could lead to double application.
I would leave them separate.

On Tue, Mar 26, 2019 at 2:11 AM James Hester <jamesrhester@gmail.com> wrote:
Dear DDLm group

A suggestion has been put forward (see https://github.com/COMCIFS/cif_core/issues/116) to clarify the meaning of enumeration ranges in the presence of SU. So instead of a hard boundary, a value may lie with +- 3su of the upper/lower boundary where it has been specified. The suggestion is to expand the _enumeration_range text as follows:

(Old text)

      The inclusive range of values "from:to" allowed for the defined item.

(New text)

      The inclusive range of values "from:to" allowed for the defined item. If items have associated SU, the value must lie in the 99.97% Gaussian confidence interval 
(lower_limit -3u) =< x =< (upper_limit + 3u). 


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