Refer to the American Journal of Science (Jan. 2005) study of the chemical makeup of buried glacial drifts (or tills) in Wisconsin, Exercise 2.22. The ratio of aluminum (Al) to beryllium (Be) in sediment for each of a sample of 26 buried till specimens is given in the table at the bottom of the page.

a. Recall that the researchers desired an estimate of the proportion of till specimens in Wisconsin with an Al/Be ratio that exceeds 4.5. Compute this estimate from the sample data. 

b. Form a 95% confidence interval around the estimate, part a. Interpret the interval.

Data from Exercise 2.22

Tills are glacial drifts consisting of a mixture of clay, sand, gravel, and boulders. Engineers from the University of Washington’s Department of Earth and Space Sciences studied the chemical makeup of buried tills in order to estimate the age of the glacial drifts in Wisconsin. (American Journal of Science, Jan. 2005.) The ratio of the elements aluminum (Al) and beryllium (Be) in sediment is related to the duration of burial.

Transcribed Image Text:

TILLRATIO 3.75 4.05 3.81 3.23 3.13 3.30 3.21 3.32 4.09 3.90 5.06 3.85 3.88 4.06 4.56 3.60 3.27 4.09 3.38 3.37 2.73 2.95 2.25 2.73 2.55 3.06