As long as two people have different opportunity costs, each can gain from trade with the other, since trade allows each person to obtain a good at a price lower than his or her opportunity cost

The Phillips curve is a negative empirical relationship between

A) bond prices and interest rates. B) unemployment and output. C) inflation and the real interest rate. D) unemployment and inflation.

When economists David Gould, G.L. Woodbridge, and Roy Ruffin examined the data on the relationship between increases in imports and the rate of unemployment, they concluded that

A) free trade leads to increased unemployment. B) there is not a casual link between increases in imports and the rate of unemployment. C) increases in imports always precede increases in unemployment by a period of 6 months to one year. D) increases in unemployment always precede increases in imports by a period of 6 months to one year.