Radioactive lichen. Refer to the Lichen Radionuclide Baseline Research project to monitor the level of radioactivity in lichen, presented in Exercise 7.133

(p. 388). Recall that University of Alaska researchers collected nine lichen specimens and measured the amount of the radioactive element cesium-137 (in microcuries per milliliter) in each specimen. Assume that in previous years the mean cesium amount in lichen was m = .003 microcurie per milliliter. Is there sufficient evidence to indicate that the mean amount of cesium in lichen specimens differs from this value? Use the SAS printout below to conduct a complete test of hypothesis at a = .10.

Transcribed Image Text:

Sample Statistics for CESIUM N Mean 9 0.0090 Std. Dev. Std. Error 0.0049 0.0016 Hypothesis Test Null hypothesis: Mean of CESIUM = 0.003 Alternative: Mean of CESIUM 0.003 t Statistic Df Prob > t 3.725 8 0.0058