Last year, a retired schoolteacher moved her parents from Michigan to northern Illinois to live with her. For the past year, she was traveling two times each month to provide care for this eighty-six year old couple, including coordinating medical services and meals. In conversations with her family members, the teacher remarked, "If I were not already retired, I would have to quit my job to continue this way!" This retired teacher.

Mankiw attributes – chapter 1 and his 10 principles – differences in living standards within a countryover time and across countries at a moment in time to: a. the presence or absence of inflation and unemployment.b. the allocation of resources between private markets and the public sector.c. those that have dealt successfully with the efficiency v. equality tradeoff and those that haven’t.d. differences in productivity.e. ones that think at the margin and respond to incentives and those that don’t.