Re: Vineland
From: Philip Deitiker (Donevenask_at_worlnet.att.net)
Date: 02/21/05
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Date: Mon, 21 Feb 2005 14:18:46 GMT
Eric Stevens <eric.stevens@sum.co.nz> says in
news:188j11t7eq5rjg0t64u0759pio7rqgaenr@4ax.com:
> On Sun, 20 Feb 2005 22:42:34 -0700, "Tedd Jacobs"
> <Jacobs@mail.boisestate.edu> wrote:
>
>>
>>"Eric Stevens" wrote...
>>> On Sun, 20 Feb 2005 21:06:57 -0700, "Tedd Jacobs"
>>> <Jacobs@mail.boisestate.edu> wrote:
>>>
>>>>
>>>>"Eric Stevens" wrote...
>>>>> On Sun, 20 Feb 2005 17:30:21 -0700, "Tedd Jacobs"
>>>>> <Jacobs@mail.boisestate.edu> wrote:
>>>>>
>>>>>>
>>>>>>"Eric Stevens" wrote...
>>>>>>> On Sun, 20 Feb 2005 14:19:25 -0700, "Tedd Jacobs"
>>>>>>> <Jacobs@mail.boisestate.edu> wrote:
>>>>>>>
>>>>>>>>
>>>>>>>>"Eric Stevens" wrote...
>>>>>>>>> On Sun, 20 Feb 2005 13:41:25 +0100, Lukas Pietsch
>>>>>>>>> <lukas.pietsch@invalid-uni-hamburg.de> wrote:
>>>>>>>>>
>>>>>>>>>>Eric Stevens wrote:
>>>>>>>>>>> Lukas Pietsch wrote:
>>>>>>>>>>>>Eric Stevens wrote:
>>>>>>>>>>>>
>>>>>>>>>>>>>But in neither case do they give an absolute date
>>>>>>>>>>>>>(with, or without,
>>>>>>>>>>>>>confidence limits).
>>>>>>>>>>>>
>>>>>>>>>>>>... Which, as a lot of people have been pointing out
>>>>>>>>>>>>to you, is not
>>>>>>>>>>>>a
>>>>>>>>>>>>necessary criterion for the term "dating" to apply.
>>>>>>>>>>>>Get it?
>>>>>>>>>>>>
>>>>>>>>>>> This argument started off using the specific
>>>>>>>>>>> meaning of posts by nibblenob@lycos.com and Seppo
>>>>>>>>>>> Renfors. A date range was not under consideration in
>>>>>>>>>>> that context.
>>>>>>>>>>
>>>>>>>>>>Of course it was. The discussion started out from
>>>>>>>>>>Rodney's assertion that "the ink dated after 1930"
>>>>>>>>>>(which is as clear a reference to
>>>>>>>>>>"dating-qua-terminus-post-quem" as you can get).
>>>>>>>>>>
>>>>>>>>>>> Seppo had said the
>>>>>>>>>>> ink had never been dated and I believe he is correct
>>>>>>>>>>> in that respect.
>>>>>>>>>>
>>>>>>>>>>I am at a loss to reconcile this with your answer to my
>>>>>>>>>>other post, which you sent off the same minute as this
>>>>>>>>>>one. I had said:
>>>>>>>>>>
>>>>>>>>>> >> The VM has
>>>>>>>>>> >> been "dated" in that sense [i.e. by
>>>>>>>>>> >> terminus-post-quem]. For me, that is a legitimate
>>>>>>>>>> >> instance of "dating" if ever there was one.
>>>>>>>>>>
>>>>>>>>>>To which you agreed:
>>>>>>>>>> > I accept all that [...]
>>>>>>>>>>
>>>>>>>>>>How can you at the same time accept my saying that there
>>>>>>>>>>was dating and
>>>>>>>>>>Seppo's saying that there was none?
>>>>>>>>>>
>>>>>>>>>> > [...] but in the particular circumstances in which
>>>>>>>>>> > the discussion started the question was over whether
>>>>>>>>>> > or not the ink had ever been dated to after 1930 (by
>>>>>>>>>> > any means).
>>>>>>>>>>
>>>>>>>>>>How do you reconcile this statement with your statement
>>>>>>>>>>above that "a
>>>>>>>>>>date range was not under consideration in that context"?
>>>>>>>>>>How is "dated
>>>>>>>>>>to after 1930" *not* a consideration of a date range?
>>>>>>>>>>
>>>>>>>>> We are now arguing about definitions and terminology.
>>>>>>>>>
>>>>>>>>> I have always made clear that I have been
>>>>>>>>> differentiating between assigning the ink to a specific
>>>>>>>>> date and assigning the ink to a date range. I prefer to
>>>>>>>>> make the distinction clear while you see no real
>>>>>>>>> distinction. The important thing is not whose usage is
>>>>>>>>> (the most) correct but whether or not we understand each
>>>>>>>>> other.
>>>>>>>>
>>>>>>>>i'll go you one better and tell you that assigning a
>>>>>>>>"specific date" to
>>>>>>>>anything is impossible. and that the best anyone can do is
>>>>>>>>assign a "date
>>>>>>>>range". so if setting a "specific date" is impossible, and
>>>>>>>>the best we can
>>>>>>>>do is assign a "date range", then by "dating" we can only
>>>>>>>>mean a "date range". in which case if a "date range" has
>>>>>>>>been assigned to something
>>>>>>>>it
>>>>>>>>qualifies as having been "dated". the major premise here
>>>>>>>>in which the entire argument is predicated upon is that
>>>>>>>>assigning a "specific date" is
>>>>>>>>impossible. care to dance? (i'm looking for a reason to
>>>>>>>>avoid studying
>>>>>>>>for
>>>>>>>>mid-terms here.) ;-)
>>>>>>>>
>>>>>>>>
>>>>>>> Surely you are not asking me to yet again go over the
>>>>>>> difference between a specific date with upper and lower
>>>>>>> confidence limits and a date range with upper and lower
>>>>>>> limits (which may have their own conficence limits)?
>>>>>>>
>>>>>>> No, I thought not. :-)
>>>>>>
>>>>>>no. i am saying there is no such thing as a specific date
>>>>>>for anything. your differences between 'specific date' and
>>>>>>'date range' are irrelevent when 'specific date' doesnt
>>>>>>exist and all we are left with is a date range.
>>>>>>
>>>>>>
>>>>> Radiocarbon, for example, does not give you a date range.
>>>>
>>>>okay, what does it give?
>>>>
>>> It gives you a specific date with upper and lower confidence
>>> limits.
>>>
>>> See http://www.c14dating.com/agecalc.html and links, starting
>>> with:
>>>
>>> "We mentioned previously that statistical analysis is
>>> necessary in
>>> radiocarbon dating because the decay of C14 although
>>> constant, is spontaneous. It is not possible to measure all
>>> of the radioactivity in a given sample, hence the need for
>>> some kind of statistical analysis of counted data. The
>>> distribution of counted C14 decay events will, over time,
>>> yield a pattern. The pattern is termed a "normal
>>> distribution curve". A normal or "Gaussian" distribution
>>> describes the symmetrical bell shaped cluster of events
>>> around the average or mean of the data. In a normal
>>> distribution, 2 out of 3, or 68% of the values or counts
>>> observed will fall within one standard deviation of the
>>> average of the data. At two standard deviations, 95% of the
>>> observed counts will fall within the range and at three
>>> standard deviations, 99% of the counts which comprise the
>>> normal distribution will fall within this region. [This
>>> illustrates what I have been saying about t date is
>>> released as a conventional radiocarbon age with 'standard
>>> error'. This is the '±' value and by convention is ± 1
>>> sigma. The standard error is based principally upon
>>> counting statistics (but see below).
>>>
>>> According to Stuiver and Pearson (1992), the majority of
>>> laboratories report the measured counting statistics as a
>>> laboratory standard error. This results in considerable
>>> under-reporting (Scott, Long and Kra, 1990:253-393; Stuiver
>>> and Pearson, 1992:20) because a standard error based upon
>>> counting statistics alone does not include additional errors
>>> which may be incurred, for example, during sample
>>> preparation. Pearson (1979:21) has suggested: "
>>>
>>> This last illustrates the point I have been making about
>>> experimental error. Additional errors are introduced by
>>> everything from the quality of the standards used to
>>> uncertainty of the data upon which the calibration curves are
>>> based.
>>>
>>> In the end, an important question is 'how confident do you
>>> need to be in the final date?'
>>sorry eric, but nowhere does it state that c14 gives a specific
>>date. it does however talk about "age of a sample within the
>>range":
>>
>>/quote/
>>"Accuracy and Precision in Radiocarbon dating
>>
>>It is important to note the meaning of "accuracy" and
>>"precision" in radiocarbon dating. Accuracy refers to the date
>>being a 'true' estimate of the age of a sample within the range
>>of the statistical limits or ± value of the date. Thus, for the
>>sake of argument, if we were radiocarbon dating a sample of
>>Harold 1's (d. 1066) remains, and obtained a date of 1040±40 AD,
>>we would have dated the event of his death accurately. If
>>however the date were 1000±15 AD, we would be inaccurate. In
>>terms of precision, however, the former is imprecise in
>>comparison to the latter. It can be seen that the date of
>>1000±15 AD while being highly precise is, in this instance,
>>inaccurate." /end quote/
>
> One of us doen't understand what the other is talking about.
>
> What do YOU think it means when you write 1040±40 AD? Do you
> think it means there is an equal probability of it being any
> where between 1000 AD and 1080 AD? Would yo go further and say
> there is NO probability of it being 999 AD or 1081 AD?
>
> I will leave the 1000±15 AD until you have explained what you
> meant about the 1040±40 AD.
You seem to fail to understand the nuances of error and distribution.
In general a range is the highest possible or lowest possible event,
for example, lets say that someone positively concluded that Anastase
was a certain particle size could only come from a single process.
And the individual looked at all parchments and he found 12
parchments with anatase. and the distribution was
1920, 1922, 1923, 1924, 1924, 1925, 1925, 1925, 1926, 1926, 1927,
1929. 1920-1928 is the range, but the distribution has also a mean,
1925 and a std. deviation about the mean. The distribution is normal.
Not all distribtions are normal, in fact in science distributions are
infrequently normal, and a scewed. The distribution can be more
flattened, it can have a sharper central peak, it can be bimodal.
These are still distributions, a range is a measured parameter of a
distribution, it is a quality of the sample set, just like the mean
and the std. variance, skew, etc. Range does not set the outer limit
of the distribution unless you are measuring the entire population,
in which case one needs to state that. Range will generally increase
(increasingly more slowly) with N.
-- Philip - - - - - - - - - - - - - - - - - - - - - - - - - - - ____Groups_____ Mol Anthro http://groups.yahoo.com/group/DNAanthro/ Pal Anthro http://groups.yahoo.com/group/Paleoanthro/ Arch. Aux http://groups.yahoo.com/group/sciarchauxilliary/ Gliadin Sci http://health.groups.yahoo.com/group/GliadinScience/ ____Sites_____ Mol. Evol. Hominids http://home.att.net/~DNAPaleoAnth/ Evol. of Xchrom. http://home.att.net/~DNAPaleoAnth/xlinked.htm
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