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Archiver > GENEALOGY-DNA > 2008-05 > 1211497766


From: "Ken Nordtvedt" <>
Subject: Re: [DNA] S21/S28 Split+m223 stuff
Date: Thu, 22 May 2008 17:09:26 -0600
References: <200805222225.m4MMOjG2031281@mail.rootsweb.com><82D9516D-5362-4241-A934-9404242CDC06@vizachero.com>


There are two (actually three) weighting schemes. If you talk in terms of G
= Sum [w(i) G(i) ] / Sum [ w(i) ]

with w(i), m(i), Var(i) and G(i) = Var(i) / m(i) being weight, mutation
rate, variance, and individual G estimate for each marker, respectively

Heald is using w(i) = 1
Text book and my present individual clade G is using w(i) = m(i)
My "weighted" computation for interclade Gs uses w(i) = m(i) / (1 + 2 m(i)
G ) at iterative convergence.



----- Original Message -----
From: "Vincent Vizachero" <>
To: <>
Sent: Thursday, May 22, 2008 4:52 PM
Subject: Re: [DNA] S21/S28 Split+m223 stuff


> Apologies for confusing your use of their summation formulas with
> your use of their tools.
>
> However, the summation formula used by Ken and the summation formula
> used by James (if I am reading the archive correctly) appear to
> effectively put more more and less emphasis (respectively) on the
> most mutative markers. I agree that neither method employs an
> explicit weighting scheme, but the effect is similar.
>
> Anyway, the two formulas produce different relative ages for R-S21
> and R-S28.
>
> Vince
>
>
> On May 22, 2008, at 6:24 PM, Tim Janzen wrote:
>
>> As Ken mentioned in his last message, neither of us have weighted
>> the markers in our spreadsheets. I am currently working on helping
>> Ken with
>> the issue of weighting the markers.
>
>
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