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Author Topic:   Statistical analysis of tree rings
JonF
Member (Idle past 198 days)
Posts: 6174
Joined: 06-23-2003


Message 1 of 2 (503725)
03-21-2009 2:51 PM


In Message 335 in a now-closed thread, Daniel4140 wrote:
quote:
quote:
ETA; Whoops, the bristlecone measurements aren't labeled as such in the file. They are at North America Paleo Tree Ring Measurements.
You might want to read Biblical Chronology and the 8,000-Year-Long Bristlecone Pine Tree-Ring Chronology
Good link. So there is some data. I looked at four matches from ca. 1700 B.C., and did a few tests. First for the 'matching' sections I subtracted the ring withs to produce a difference table. I then found the average difference, and then the mean. Here is the start of the data for MWK001 and MWK002 cross match.
-1754 17.69%
-1753 Median 13 Avdif 2.3
-1752 MWK001 MWK002
-1751
-1750 15 21
-1749 13 17
-1748 14 22
-1747 12 18
-1746 16 27
-1745 16 21
-1744 14 13
-1743 15 15
-1742 20 22
This just a back of the envelope calculation. I did the same for a match in the last 500 years with similar results. Here is part of the data:
1616 26.25%
1617 Median 16
1618 Avdif 4.2
1619 MWK832
1620 18
1621 11
1622 0
1623 22
1624 13
1625 21
1626 4
Then I took this same section and deliberately missmatched it against another section. Here is the result:
Random Control Test #1
18 8.98 49.89%
22 3
14 18
14 5
19 1
11 1
22 3
2 27
The average deviation from the median ring width goes up to 49% of the median. I then performed the same tests on linkages between 4000 B.C. and 2000 B.C.
Test 1: 61%
Test 2: 79%
Test 3: 99%
Test 4: 47%
Test 5: 51%
Test 6: 49%
Test 7: 48%
Test 8: 45%
This was good enough to convince me that the whole statistical method of cross matching is highly subjective. The critical matches before 2000 B.C. seem to be no more than white noise.
...
I have read the AIG Woodmorerappe article. I disagree with John's quick rubber stamping of the statistical results on the basis that I have been unable to find a control test on a non-matching sample, plus have read allegations of others who have done just that with non-confirming results.
And, in Message 352:
quote:
You are the one misrepresenting the data. Why didn't you point out this discrepancy in the first place? Why did I have to dig it up?
And if you don't cite all the discrepant data, then why should I assume that those researchers didn't dump a lot of discrepant dates before they got some that agreed with their theory? Your "science" is just divination.
  1. It's unclear what the results of your tests are. You write "The average deviation from the median ring width goes up to {emphasis added} 49% of the median" and then provide a table of other claculations in which the percentages are about equal to or larger than 49%. These are much larger than the percentages listed above for the "correct" matches, and suggest that your chosen test is indeed indicating that mismatches are mismatches. If this is not so, plese explain in more detail.
  2. You write "This was good enough to convince me that the whole statistical method of cross matching is highly subjective." Since it appears that you are not using the statistical methods used by professionals, I don't see why you come to this conclusion. The results of your method provides no information about the objectivity or subjectivity of other methods.
  3. Hearing of allegations is not evidence. If you have evidence of "others who have done just that with non-confirming results" trot it out. If you do not have evidence, drop the subject.
  4. As far as I can tell, there is no discrepancy to point out. You have made a claim but have a long way to go in supporting that claim.
  5. I'm sure RAZD will start another correlation topic soon.

AdminNosy
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From: Vancouver, BC, Canada
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Message 2 of 2 (503733)
03-21-2009 4:12 PM


Thread copied to the Statistical analysis of tree rings thread in the Dates and Dating forum, this copy of the thread has been closed.

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