Warm-Up Chp. 23: One Sample CI/HT for Means
The composition of the earth's atmosphere may have changed over time. One attempt to
discover the nature of the atmosphere from long ago involves studying the gas trapped in
bubbles inside ancient amber tree resin that has hardened and been trapped in rocks.
Assume the nitrogen gas bubbles trapped within the amber should be a sample of the
atmosphere at the time the amber was formed. Measurements of percent of nitrogen from
amber from the late Cretaceous era, 75-95 million years ago, are as follows:
63.4, 65.0, 64.4, 63.3, 54.8, 64.5, 60.8, 49.1, 51.0.
These values are quite different from the present 78.1% of nitrogen in the atmosphere,
but are those differences significant?
i Pop
Parunoter:
Construct a 95% confidence interval for the mean percent of nitrogen in the late Cretaceous era. Is this consistent with the results from the HT?