Selling Treasury bonds to finance a federal deficit crowds out private investment by driving interest rates down.

To help unscramble cause and effect, economists

A) use the concept of opportunity costs. B) must use the ceteris paribus assumption. C) answer the "what" question. D) answer the "how" question. E) must use normative statements.

The intersection of the aggregate supply curve and the aggregate demand curve occurs at the economy's equilibrium level of

A) real investment and interest rate B) real disposable income and unemployment C) real national output and the price level D) government expenditures and taxes E) imports and exports