9.44. In 2002, a Census Bureau survey reported that the mean total earnings that a full-time worker in the U.S. can expect to earn between ages 25 and 64 is $1.2 million for those with only a high-school education and $2.1 million for those with a college degree but no advanced degree.

(a) Assuming four years for a college degree and a straight line regression ofy = total earnings on.r = number years of education, what is the slope?

(b) Ify instead measures earnings per year (rather than for 40 years), then what is the slope?