What new developments starting in the 1980s have changed macroeconomic thought?

Suppose your rich uncle gave you $50,000, which you plan to use for graduate school. you will make the investment now, you expect to earn an annual return of 6%, and you will make 4 equal annual withdrawals, beginning 1 year from today. under these conditions, how large would each withdrawal be so there would be no funds remaining in the account after the 4th?

Saks fifth avenue wants to learn about its consumers' attitudes toward on-line purchases. there are numerous studies that are available about consumers and on-line buying, but saks believes its customers might be different from the usual on-line consumer profile, so they decide to conduct their own study. if saks were to use the available data about consumer attitudes, it would be using data; however, if saks does its own study it would collect data.

Rose bought a mattress for her guest bedroom for $100, on sale. the mattress is nonreturnable. although everyone who has slept on the mattress said it was very uncomfortable, rose will not get rid of it because she spent $100 on it. what psychological factor associated with behavioral economics explains rose's behavior?