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Re: [ccp4bb] difference between I over sigma I and I over sd
 

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CCP4bb <-- 2008 <-- January 2008 <-- 21 January 2008
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Subject: Re: Spacegroup choices, reindexing and so on
From: "Manfred S {- dot -} Weiss" msweiss {- at -} EMBL-HAMBURG {- dot -} DE
Date: 2008-01-21 		Next message:
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From: "Manfred S {- dot -} Weiss" msweiss {- at -} EMBL-HAMBURG {- dot -} DE
Date: 2008-01-21


Subject: Re: difference between I over sigma I and I over sd
From: Eleanor Dodson ccp4 {- at -} YSBL {- dot -} YORK {- dot -} AC {- dot -} UK
Date: 2008-01-21
LLI agree the difference between sd and SigI are a bit obscure. One
referes to the spread of values about your mean I (The Sd of the
reflection distribution)
SigI is derived from the SIGI values estimated by the integration.
There is some description in the CCP4 study weekend article by Phil Evans

/Acta Cryst./ (2006). D*62*, 72-82 [ doi:10.1107/S0907444905036693 ]


Scaling and assessment of data quality


P. Evans

*
*

http://journals.iucr.org/d/issues/2006/01/00/issconts.html

Cant answer the PDB Q - I guess there should be a manual on their web site?
Eleanor

u Yongzhi wrote:
> Hi everyone,
>
> When I scale the data using Scala, I don't know differences between
> _diffrn_reflns.meanI_over_sigI_all 6.5475
> _diffrn_reflns.meanI_over_sd_all 21.3013
> in the statistics. I think that both "sigma" and "sd" have the same meaning--"standard deviation". By the way, in the file header of PDB's, what are the meanings of the numbers 5 and 1 in the row "HELIX", numbers 0, 1 and -1 in the row "SHEET". And in the row "SHEET", what's the meaning of the last 6 columns.
> HELIX 1 1 THR A 35 ASP A 37 5 3
> HELIX 2 2 SER A 41 TYR A 46 1 6
> HELIX 3 3 GLU A 68 ALA A 82 1 15 SHEET 1 C 6 GLU A 224 ARG A 232 0
> SHEET 2 C 6 ILE A 214 GLU A 221 -1 N CYS A 217 O ARG A 229
> SHEET 3 C 6 PHE A 183 VAL A 189 -1 N PHE A 187 O LEU A 218
> SHEET 4 C 6 VAL A 302 LEU A 309 -1 O ILE A 306 N LYS A 184
> SHEET 5 C 6 LYS A 254 HIS A 261 -1 N ILE A 258 O GLY A 305
> SHEET 6 C 6 GLU A 280 PRO A 288 1 O ASP A 283 N VAL A 257
>
>
> Thanks
>
> Lu Yongzhi

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CCP4bb <-- 2008 <-- January 2008 <-- 21 January 2008
Previous message:
Subject: Re: Spacegroup choices, reindexing and so on
From: "Manfred S {- dot -} Weiss" msweiss {- at -} EMBL-HAMBURG {- dot -} DE
Date: 2008-01-21 		Next message:
Subject: Announcement - EMBO World Lecture Course
From: "Manfred S {- dot -} Weiss" msweiss {- at -} EMBL-HAMBURG {- dot -} DE
Date: 2008-01-21


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