Refer to the American Journal of Science (Jan., 2005) study of the chemical makeup of buried glacial drifts (tills), Exercise 2.22 (p. 38). The data on the Al/Be ratios for a sample of 26 buried till specimens are repeated in the table.

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. The Al/Be ratios for a sample of 26 buried till specimens are given in the table. With the aid of a graph, estimate the proportion of till specimens with an Al/Be ratio that exceeds 4.5.

a. Compute and interpret three numerical descriptive measures of central tendency for the Al/Be ratios.

b. Compute and interpret three numerical descriptive measures of variation for the Al/Be ratios.

c. Construct a box plot for the data. Do you detect any outliers?

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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