Randomized control trials can help economists evaluate the impact of global aid programs in the same way that doctors test drugs

The largest source of federal government revenue in the United States is

A) corporate income taxes. B) individual income taxes. C) payroll taxes. D) excise taxes.

"Duopoly" is

A) another name for monopoly. B) a special type of monopolistic competition. C) a two-firm oligopoly. D) a game with three players. E) the situation when a firm sets a duo (two) of different prices for its customers.