Retail Forward, Inc., is a global management consulting and market research firm specializing in retail intelligence and strategies. One of its press releases (June Consumer Outlook: Spending Plans Show Resilience , June 1, 2006) divulged the result of the Retail Forward ShopperScape™ survey conducted each month from a sample of 4,000 U.S. primary household shoppers. A measure of consumer spending is represented by the following figure:

a. Construct a time-series plot of these data. Does it appear that a linear trend exists in the time series?
b. Calculate forecasts for each of the months in the time series. Use a smoothing constant of 0.25.
c. Calculate the MAD value for the forecasts you generated in part b.
d. Construct a single exponential smoothing forecast for July 2006. Use a smoothing constant of 0.25.