Bullie Jean has $1.20 to spend and wants to buy cither a new amplifier for her guitar or a new mp3 player to listen to music while working out. Both the amplifier and the mp3 player cost $120, so she can only buy one. This illustrates the basic concept that:. a. trade can make everyone better off.
b. people face trade-ofts.
c. rational people think at the margin.
d. decisions made at the margin are not particularly important .

Ajustification for job training programs is that they improve worker productivity. suppose that you are asked to evaluate whether more job training makes workers more productive. however, rather than having data on individual workers, you have access to data on manufacturing firms in ohio. in particu- lar, for each firm, you have information on hours of job training per worker (training) and number of nondefective items produced per worker hour (output). (i) carefully state the ceteris paribus thought experiment underlying this policy question. (ii) does it seem likely that a firm’s decision to train its workers will be independent of worker characteristics? what are some of those measurable and unmeasurable worker characteristics? (iii) name a factor other than worker characteristics that can affect worker productivity. (iv) if you find a positive correlation between output and training, would you have convincingly established that job training makes workers more productive? explain.