Problem 18-29 (Static)

Mark Price, the new productions manager for Speakers and Company, needs to find out which variable most affects the demand for their line of stereo speakers. He is uncertain whether the unit price of the product or the effects of increased marketing are the main drivers in sales and wants to use regression analysis to figure out which factor drives more demand for their particular market. Pertinent information was collected by an extensive marketing project that lasted over the past 10 years and was reduced to the data that follow:

YEAR	SALES/UNIT (THOUSANDS)	PRICE $/UNIT	ADVERTISING ($000)
1998	400	280	600
1999	700	215	835
2000	900	211	1,100
2001	1,300	210	1,400
2002	1,150	215	1,200
2003	1,200	200	1,300
2004	900	225	900
2005	1,100	207	1,100
2006	980	220	700
2007	1,234	211	900
2008	925	227	700
2009	800	245	690

a. Perform a regression analysis based on these data using Excel. (Negative values should be indicated by a minus sign. Round your answers to 4 decimal places.)

c. Predict average yearly speaker sales for Speakers and Company based on the regression results if the price was $300 per unit and the amount spent on advertising (in thousands) was $900. (Enter your answer in thousands. Round your answer to the nearest whole number.)