Consider the profits as a percent of revenue for a group of companies involved in petroleum and/or mining, as shown in Table 8.6.2.
a. Construct a sampling frame, viewing this list as a population of large petroleum and/or mining-related firms.
b. Draw a random sample of 10 firms, starting from row 13, column 2 of the table of random digits.
c. Compute the sample average.
d. Compute the standard error of the average, both with and without use of the finite-population correction factor.
e. Write a paragraph explaining and interpreting the standard error.
f. Compute the population mean.
g. Write a brief paragraph explaining the relationship among the sample average, population mean, and standard error.

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TABLE 8.6.2 Profit for Petroleum and/or Mining Firms Profit as a Percent of Revenue Firm Anadarko Petroleum Apache Baker Hughes Cameron International Chesapeake Energy Chevron ConocoPhillips Consol Energy -1.50% 3.30 4.36 9.10 -75.70 6.41 3.48 11.68 Continued) TABLE 8.6.2 Profit for Petroleum and/or Mining Firms-cont'd Profit as a Percent of Revenue -27.67 -11.64 Firm Devon Energy El Paso Enbridge Energy Partners Energy Transfer Equity Enterprise GP Holdings EOG Resources Exxon Mobil Freeport-McMoRan Copper & 8.17 11.42 18.28 Halliburton 7.80 0.41 Kinder Morgan Marathon Oil Murphy Oil National Oilwell Varco Newmont Mining Occidental Petroleum 6.90 11.56 16.76 18.77 7.10 3.13 1.81 17.95 Peabody Energy Plains All American Pipeline Smith International Spectra Energy Sunoco Tesoro Valero Energy Westem Refining XTO Energy -0.84 -2.83 -5.15