Sales of a particular product (in thousands of dollars) for the years 2009 through 2012 have been $48,000, $64,000, and $83,000, respectively.

a. What sales would you predict for 2013, using a simple four-year moving average?
b. What sales would you predict for 2013, using a weighted moving average with weights of 0.50 for the immediate preceding year and 0.3, 0.15, and 0.05 for the three years before that?

Which (if any) of the following scenarios is the result of a natural monopoly? instructions: you may select more than one answer. a. patent holders of genetically modified seeds are permitted to sue farmers who save seeds from one planting season to the next. b. doctors in the united states are prohibited from practicing without a medical license. c. there is one train operator with service from baltimore to philadelphia. d. coal is used as the primary energy in a country with abundant coal deposits.