1. the phillips curve shows that in the short-run:
a. unexpected changes in aggregate demand produce an inverse relationship between inflation and unemployment.
b. unexpected changes in aggregate demand produce a positive relationship between inflation and unemployment.
c. expected changes in aggregate demand produce a positive relationship between inflation and unemployment.
d. expected changes in aggregate demand produce an inverse relationship between inflation and unemployment.

2. suppose people expect the inflation rate to be 3 percent. the government engages in a one-time expansionary monetary policy in order to lower unemployment. once people realize what has happened:
a. the phillips curve will shift inward, causing unemployment to return to its natural rate.
b. there will be a movement along the phillips curve, causing the inflation rate to return to 3 percent.
c. the phillips curve will shift outward, causing unemployment to return to its natural rate.
d. there will be a movement down along the phillips curve, causing unemployment to return to its original level.

It is widely assumed that people need to engage in intellectual activities such as solving crossword puzzles or mathematics problems in order to maintain mental sharpness as they age. in fact, however, simply talking to other people—that is, participating in social interaction, which engages many mental and perceptual skills—suffices. evidence to this effect comes from a study showing that the more social contact people report, the better their mental skills. which of the following, if true, most seriously weakens the force of the evidence cited? (a) as people grow older, they are often advised to keep exercising their physical and mental capacities in order to maintain or improve them. (b) many medical conditions and treatments that adversely affect a person's mental sharpness also tend to increase that person's social isolation. (c) many people are proficient both in social interactions and in solving mathematical problems. (d) the study did not itself collect data but analyzed data bearing on the issue from prior studies. (e) the tasks evaluating mental sharpness for which data were compiled by the study were more akin to mathematics problems than to conversation.