When bad storms slow the check-clearing process, float tends to ________ causing the Fed to initiate defensive open market ________

In the figure above, the equilibrium market price is $20. The producer surplus equals

A) $20. B) $1,500. C) $3,000. D) 150. E) $4,500.

The following does not represent a threat to internal validity of randomized controlled experiments:

A) attrition. B) failure to follow the treatment protocol. C) experimental effects. D) a large sample size.