Below you are given a partial computer output based on a sample of 12 observations relating to the number of personal computers sold by a computer shop per month (y), unit price (x₁ in $1000), and the number of advertising spots (x₂) used on a local television station.

	Coefficients	Standard Error
Constant	17.145	7.865
x1	-0.104	3.282
x2	1.376	0.250

a.	Use the output shown above and write an equation that can be used to predict the monthly sales of computers.
b.	Interpret the coefficients of the estimated regression equation found in Part a.
c.	If the company charges $2000 for each computer and uses 10 advertising spots, how many computers would you expect them to sell?
d.	At α = .05, test to determine if the number of advertising spots is a significant variable.