In 2011 through 2014, the value of precious metals fluctuated dramatically. The data in the following table (stored in Metals) represent the total rate of return (in percentage) for platinum,
gold, and silver from 2011 through 2014:
Year Platinum Gold Silver
2011 -21.1 10.2 -9.8
2012 8.68 0.1 7.1
2013 -11.7 6.08 7.13
2014 -0.72 -28.65 -26.65
Source: Data extracted from finance. yahoo. com,
May 5, 2015.
a. Compute the geometric mean rate of return per year for platinum, gold, and silver from 2011 through 2014.
b. What conclusions can you reach concerning the geometric
mean rates of return of the three precious metals?

Farmers know that driving heavy equipment on wet soil compresses the soil and injures future crops. here are data on the "penetrability" of the same type of soil at two levels of compression. penetrability is a measure of how much resistance plant roots will meet when they try to grow through the soil. compressed soil 2.85 2.66 3 2.82 2.76 2.81 2.78 3.08 2.94 2.86 3.08 2.82 2.78 2.98 3.00 2.78 2.96 2.90 3.18 3.16 intermediate soil 3.17 3.37 3.1 3.40 3.38 3.14 3.18 3.26 2.96 3.02 3.54 3.36 3.18 3.12 3.86 2.92 3.46 3.44 3.62 4.26 use the data, omitting the high outlier, to give a 95% confidence interval for the decrease in penetrability of compressed soil relative to intermediate soil. compute degrees of freedom using the conservative method. interval: to