1. The Florida ecosystem is heavily reliant on wet and dry seasons, and is particularly dependent on the winter and spring rainfall that helps reduce damage due to wildfires. Data file XR15013 lists the number of acres burned and the number of inches of rainfall during January-May for 1988-2000. Given these data, deter- mine the least-squares equation for predicting acreage burned during the January-May period as a function of rainfall during that period, then interpret its slope. What would be the estimated number of acres burned during January-May if there were 18 inches of rainfall during the same period? Source: "Rainfall, Fires Linked In Florida," USA Today, June 9, 2000, p. 4A.
2. For the leading health maintenance organiza- tion (HMO) firms, data file XR15014 lists the number of persons enrolled in the HMO along with the number of plans the firm administers. Given these data, determine the least-squares equation for predicting the total enroll- ment as a function of the number of plans administered. What would be the estimated total enrollment for an HMO firm that administered 20 plans? Source: The Wall Street Journal Almanac 1999, p. 565.