Sentences with phrase «true calendar ages»

The problem is, what input distribution do you use in the first step, to generate the true calendar ages?

You finally filter out from the collection of trials all those with a particular measured C14 age, and look at the distributions of true calendar ages that generated it, compared against the measured calendar age distribution each algorithm output.

In these frequentist coverage tests, for each integral percentage point of probability the proportion of cases where the true calendar age of the sample falls below the upper limit given by the method involved for a one - sided interval extending to that percentage point is computed.

The blue calibration curve shows the relationship between true 14C age (on the y - axis) and true calendar age on the x-axis.

Nic:... you assume that genuine prior information exists as to the true calendar age of a sample, whereas I do not.

Using a uniform prior, the true calendar age lies outside the HPD region noticeably more often than it should, and lies beyond the top of credible regions derived from the posterior CDF twice as often as it should.

There are two values involved here — the carbon - 14 measurement, which is recorded to some number of decimal places, and the true calendar age, which we can suppose is a real number with infinite precision.

For each sampled true calendar age, a 14C determination age is sampled randomly from a Gaussian error distribution.

As HPD regions are two - sided, I compute the proportion of cases in which the true calendar age falls within the calculated HPD region for each integral percentage HPD region.

Your Fig. 6 shows that the uniform calendar age prior does terribly when the true calendar age is known to be in the range 1000 - 1100 years, using your hypothetical calibration curve.

I think the fundamental difference between us is that you assume that genuine prior information exists as to the true calendar age of a sample, whereas I do not.

Not exact matches

It's about shoving kids into programs at ridiculously young ages, before they're even able to tie their mini cleats; and it's about seeking out ultra competitive programs featuring calendar - stuffed schedules of practices, games and absurd training regimens that have sucked the true essence of childhood out of many kids» lives.

Of course, the table, so constructed, will only give the correct calibration if the tree - ring chronology which was used to construct it had placed each ring in the true calendar year in which it grew.Measurements made using specially designed, more elaborate apparatus and more astute sampling - handling techniques have yielded radiocarbon ages for anthracite greater than 70,000 radiocarbon years, the sensitivity limit of this equipment.

If we do this for a series of rings through any given chronology, we can then establish a radiocarbon calibration curve, which allows us to translate any radiocarbon age into a true calendar date.

There remains therefore finite probability that the RC Age is drawn from any true Calendar Date from 475 (say) to 750 (say) since a sample from any of these dates could give rise to the observed measurement of RC Age.

You submit a physical sample which has a particular true calendar / C14 age combination — a random point on the calibration curve — with some input distribution.

But this does not imply that the measurement has nothing to say about whether or not SOME calendar age in this range is the true age.

One can think of there being a nonlinear but exact functional calibration curve relationship s14C = c (ti) between calendar year ti and a «standard» 14C age s14C, but with — for each calendar year — the actual (true, not measured) 14C age t14C having a slightly indeterminate relationship with ti.

This can be demonstrated analytically directly from the definition of the Fisher Information for a single parameter space if a constant variance is assumed for the distribution of RC age given a calendar date, and the «true» calendar dates for testing are selected from a uniform distribution.

That way one would both get a realistic picture of what calendar age ranges were supported by the data, and a range that the true age did lie above or below in the stated percentage of instances.

However, the key point about radiocarbon dating is that the «calibration curve» relationship of «true» radiocarbon age t14C to the true calendar date ti of the event corresponding to the 14C determination is highly nonlinear.