(29-08-2026, 08:59 PM)Jorge_Stolfi wrote: You are not allowed to view links. Register or Login to view.The C14 results only say that the three Herbal bifolios that were tested were, with high probability, made within a 67 year interval centered around ~1420; more specifically, in the interval 1391-1458. They don't say that they were made within a couple of years of each other And, again, it is about equally likely that the vellum of bifolio f67-f68 was made around 1335 or around 1410.
If we found bifolio 67-68 just as a separate artifact with no other folios of the manuscript, yes, absolutely, C14 results would about equally likely date it to ~1335 or ~1410. However, I totally agree with the report that in the context of the results for the other folios it's overwhelmingly likely that this bifolio was produced around ~1420 and certainly no earlier than ~1390. The probability that it was produced circa 1335 is there, but it's certainly not of the same order as the probability that it was produced circa 1420.
Even if we ignore the other folios, there is one more issue, which maybe you can explain, because I have no real education in statistics and I don't understand what's happening here. I've marked on the image below the 2 sigma range of the measurement for f67, with the yellow horizontal band. The probabilities as computed in the report - 42.5% for 1308-1362 and 52.9% for 1385-1436, how are they computed exactly? They add up to 2 sigmas, so I assume they somehow distributed 95.4% between two buckets, but I'm not sure this was done correctly. The way I see it, no more than 45% of the yellow band passes through the ~1335 peak, while 100% of this band passes through ~1410 slope. So, if the question is "given this measurement distribution, what is the probability it corresponds to the 1335 peak or 1410 slope", I would say the numbers are 45 / (100 + 45) ~ 31% for 1335 and 100 / 145 ~ 69% for 1410 (both can be multiplied by 0.954 to make them sum up to 2 sigmas, if needed for some reason). And this is even generous, it's hard to measure this exactly from the image, maybe we are talking even 35/135=26% for 1335 vs 100/135=74% for 1410.