GENEALOGY-DNA-L ArchivesArchiver > GENEALOGY-DNA > 2007-07 > 1183892884
From: "Joe Knapp" <>
Subject: Re: [DNA] General Probability Question
Date: Sun, 8 Jul 2007 07:08:04 -0400
On 7/7/07, Eric Olson <> wrote:
> I have two historical references to a certain Margaret Carroll. The first is in an Ohio County Courthouse, where as a minor in 1818 she is seeking a legal guardian. She gives her birth date as 20 August 1802. The second record is her obituary dated 1898 that states, Margaret (Carroll ) Curry was born 20 August 1802 in Lancaster County, Pennsylvania, born of German parents.
> What are the chances these are the same person? I find that surname Carroll runs at about 1/5000 of surnames in America. The two exact birth dates seems compelling, but is there a formal way to calculate the probability they are the same person?
I don't think there's a way you could put a formal probability on it
since these are such unique situations. The closest might be if you
knew the total number of Margaret Carrolls born 20AUG1802 you could
put a lower bound on the chance these two are the same. But where
you'd go from there isn't clear.
Is she the one who is listed as a "weaver" in the 1870 and 1880
censuses? In the 1880 census she and her parents are listed as being
born in Pennsylvania. They might have gotten the parents' birthplace
wrong though. Tough to figure the absolute probability in the face of