Question

Background:

Excavations at Stonehenge uncovered a number of unshed antlers, antler tines, and animal bones. Carbon-14 dating methods were used to estimate the ages of the Stonehenge artifacts. Carbon-14 is one of three carbon isotopes found in Earth’s atmosphere. Carbon-12 makes up 99% of all of the carbon dioxide in the air. Virtually all of the remaining 1% is composed of carbon-13. By far, the rarest form of carbon isotope found in the atmosphere is carbon-14.

The ratio of carbon-14 to carbon-12 remains constant in living organisms. However, once the organism dies, the amount of carbon-14 in the remains of the organism begins to decline, because it is radioactive, with a half-life of 5730 years (the “Cambridge half-life”). So the decay of carbon-14 into ordinary nitrogen makes possible a reliable estimate about the time of death of the organism. The counted carbon-14 decay events can be modeled by the normal distribution.

The team used two different carbon-14 dating methods to arrive at age estimates for the numerous Stonehenge artifacts. The liquid scintillation counting (LSC) method utilizes benzene, acetylene, ethanol, methanol, or a similar chemical. Unlike the LSC method, the accelerator mass spectrometry (AMS) technique offers direct carbon-14 isotope counting. The AMS method's greatest advantage is that it requires only milligram-sized samples for testing. The AMS method was used only on recovered artifacts that were of extremely small size.

Question:

Stonehenge’s main ditch was dug in a series of segments. Excavations at the base of the ditch uncovered a number of antlers which bore signs of heavy use. These antlers could have been used by the builders as picks or rakes. The fact that no primary silt was discovered beneath the antlers suggests that they were buried in the ditch shortly after its completion. Another researcher, Phillip Corbin, using an archeological markings approach, had previously claimed that the mean date for the construction of the ditch was 2950 BCE. A sample of nine age estimates from unshed antlers excavated from the ditch produced a mean of 3033.1 BCE, with standard deviation 66.9 years. Assume that the ages are normally distributed with no obvious outliers. At an α = 0.05 significance level, please use the hypothesis test to testify if there is any reason to any reason to dispute Corbin’s claim?

Answer 1