Osteoporosis is a degenerative disease that primarily affects wom en over the age of 60. A research analyst wants to forecast sales of StrongBones, a prescription drug for treating this debilitating disease. She uses the model Sales = β 0 +

β 1 Pop + β 2lnc + ε , where Sales refers to the sales of StrongBones ($ millions), Pop is the number of wom en over the age of 60 (in millions), and Inc is the average income of wom en over the age of 60 ($1,000s). She collects data on 38 cities across the United States and obtains the following relevant regression results:

Coefficients Standard Error t Stat p-value Intercept 10.35 4.02 2.57 0.0199 Population 8.47 2.71 3.12 0.0062 Income 7.62 6.63 1.15 0.2661

a. What is the sample regression equation?

b. Interpret the slope coefficients.

c. Predict sales if a city has 1.5 million wom en over the age of 60 and their average income is $44,000.