In a particular country in 1998, the average worker needed to work 25 hours to produce 40 units of output. In that same country in 2008, the average worker needed to work 40 hours to produce 68 units of output. In that country, the productivity of the average worker

The fundamental reason a single-price monopoly creates a deadweight loss is that compared to the efficient outcome, the single-price monopoly

A) raises variable cost. B) raises fixed cost. C) restricts output. D) reduces the elasticity of demand.

Time Fixed Effects regression are useful in dealing with omitted variables

A) even if you only have a cross-section of data available. B) if these omitted variables are constant across entities but vary over time. C) when there are more than 100 observations. D) if these omitted variables are constant across entities but not over time.