An economist secures volunteers from her college campus and divides them into two groups that are ushered into different rooms. Both groups are given a test. Those in the first group who score 90 percent or more receive an Apple iPad. Upon exiting the room, those given iPads are offered the choice of receiving $150 in exchange for the iPad. Only a few take the exchange. Those in the second group who score 90 percent are offered either an Apple iPad or $150. About half the students choose $150. The professor uses this data to support a principle known as the endowment effect. The professor is engaging in:

Although some economists believe network externalities are important barriers to entry, other economists disagree because

A) they believe that the dominant positions of firms that are supposedly due to network externalities are to a greater extent the result of economies of scale. B) they believe that most examples of network externalities are really barriers to entry caused by the control of a key resource. C) network externalities are really negative externalities. D) they believe that the dominant positions of firms that are supposedly due to network externalities are to a greater extent the result of the efficiency of firms in offering products that satisfy consumer preferences.

Which of the following is directly included in the calculation of GDP?

A. The final sale of a brand new Cadillac. B. The appreciation in value of shares of stock. C. The sales of land to a builder. D. The sales of sand to a glassmaker.