Suppose that Jasper buys 35 quarts of bottled water each month when the price per quart is $1 . When the price declines to $0.60 per quart he buys 45 quarts each month. Find Jasper's price elasticity of demand for water?

The demand for a good is more elastic if the

A) good is a necessity. B) good has few substitutes. C) good is narrowly defined. D) supply of the good is plentiful. E) Both answers B and C are correct.

For W to be an effective control variable in IV estimation, the following condition must hold

A) E(ui) = 0 B) E(ui|Zi,Wi) = E(ui|Wi) C) E(uiuj) ? 0 D) there must be an intercept in the regression