How do i read the right date on a calibration of an artifact to date a site?

Question

if i got the following information:

% area enclosed cal AD age ranges relative area under

probability distribution

68.3 (1 sigma) cal AD 1202- 1423 1.000

95.4 (2 sigma) cal AD 1021- 1502 0.993

1594- 1613 0.007

which would be the right, or closes, date? The one with the 1.000 probability?

Answer 1

sigma = standard deviation

The value to the left of it is your confidence interval.

Almost without exception, you want to use the calibrated date which encompasses two standard deviations, and gives you about a 95% confidence interval.

This will be a wider range of dates (i.e., less precise) but it is more certain to include the correct date (i.e., more accurate).