Barbara Lynch is the product manager for a line of skiwear produced by HeathCo Industries and privately branded for sale under several different names, including Northern Slopes and Jacque Monri. A new part of Ms. Lynch’s job is to provide a quarterly forecast of sales for the northern United States: a 10-year sales history is shown below:

Sales ($000)
Year	1st Quarter	2nd Quarter	3rd Quarter	4th Quarter
2007	$72,962	$81,921	$97,729	$ 142,161
2008	145,592	117,129	114,159	151,402
2009	153,907	100,144	123,242	128,497
2010	176,076	180,440	162,665	220,818
2011	202,415	211,780	163,710	200,135
2012	174,200	182,556	198,990	243,700
2013	253,142	218,755	225,422	253,653
2014	257,156	202,568	224,482	229,879
2015	289,321	266,095	262,938	322,052
2016	313,769	315,011	264,939	301,479

a). Ms. Lynch has hired you to help with the forecasting effort. First, she would like you to prepare a time-series plot of the data and to write her a memo indicating what the plot appears to show and whether it seems likely that a simple linear trend would be useful in preparing forecasts.

b). In addition to plotting the data over time, you should estimate the least-squares trend line in the form:

c). Do your regression results indicate to you that there is a significant trend to the data? Explain why or why not.

d). On the basis of your results, prepare a forecast for the four quarters of 2017.

e). A year later, Barbara gives you a call and tells you that the actual sales for the four quarters of 2017 were: Q1 = 334,271, Q2 = 328,982, Q3 = 317,921, and Q4 = 350,118. How accurate was your model? What was the mean absolute percentage error (MAPE)?