The following data show U.S. production of motor vehicles versus tons of domestic steel shipped for motor vehicle manufacture.
a. Determine the least-squares regression line and calculate r.
b. What proportion of the variability in steel shipments for motor vehicles is explained by the regression equation?
c. During a year in which U.S. production of motor vehicles is 12.0 million, what would be the prediction for the number of tons of domestic steel used for vehicle production?