Problem

Radioactive lichen. Refer to the 2003 Lichen Radionuclide Baseline Research project to mon...

Radioactive lichen. Refer to the 2003 Lichen Radionuclide Baseline Research project to monitor the level of radioactivity in lichen, Exercise 6.67 (p. 328). Recall that University of Alaska researchers collected 9 lichen specimens and measured the amount of the radioactive element cesium-137 (in microcuries per milliliter) in each specimen. (The natural logarithms of the data values, saved in the LICHEN file, are listed in the next table.) In Exercise 6.67, you used the t-statistic to test whether the mean cesium amount in lichen differs from μ = .003 microcurie per milliliter. Use the MINITAB printout below to conduct an alternative nonparametric test at a = .10. Does the result agree with that of the t-test from Exercise 6.67?

LICHEN

Location
Bethel	−5.50	−5.00
Eagle Summit	−4.15	−4.85
Moose Pass	−6.05
Turn again Pass	−5.00
Wickersham Dome	−4.10	−4.50	−4.60

Source: Lichen Radionuclide Baseline Research project, 2003.

MINITAB output

Exercise 6.67

Radioactive lichen. Refer to the 2003 Lichen Radionuclide Baseline Research project to monitor the level of radioactivity in lichen, presented in Exercise 5.35 (p. 274). 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. (The natural logarithms of the data values are saved in the LICHEN file.) Assume that in previous years the mean cesium amount in lichen was μ = .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 α = .10.

SAS output