Answer: Macroeconomics examines economic problems that influence the whole
5. The Environmental Protection Agency asks you to help them understand the causes of urban
pollution. Air pollution problems are worse the higher the Air Quality Index. You develop the following
two hypotheses.
Hypothesis I: Air pollution will be a greater problem the higher the average temperature in the urban area.
Hypothesis II: Air pollution will be a greater problem, the greater the population of the urban area.
Test each hypothesis with the facts given below. Which hypothesis fits the facts better? Have you
developed a theory?
Metropolitan Days with Average Maximum Population
Statistical Area Polluted Air* Temperature (thousands)
Cincinnati, OH 30 64.0 1,979
El Paso, TX 13 77.1 680
Milwaukee, WI 12 55.9 1,690
Atlanta, GA 24 72.0 4,112
Philadelphia, PA 33 63.2 5,101
Albany, NY 8 57.6 876
San Diego, CA 20 70.8 2,814
Los Angeles, CA 80 70.6 9,519
*Air Quality Index greater than 100 (2002) Source: U.S. Dept. of Commerce, Bureau of Census, 2002
Statistical Abstract of the United States, Tables Nos. 30, and 363; U.S. EPA, Air Trends Report, 2002,
EPA.Gov/airtrends/Factbook.
Answer: The data support the second hypothesis better than the first. The number of days
.