A marketing manager is studying the relationship between the sales and various marketing expenditures to determine the most successful techniques in the companys marketing mix. Analysis of the data produced the following multivariate regression output (in thousands $$):

	Unstandardized coefficients
	B	St. Error	Sig.
(Constant)	800.2	108.633	0.415
TV advertising expenditures	0.22	0.996	0.000
Print advertising expenditures	-0.15	9.828	0.000
Promotional expenditures	2.7	3.609	0.001
Social media marketing expenditures	0.17	0.554	0.031

R=0.61

1. Write down the regression equation. What seems to be the effect of each independent variable on the dependent variable? Based on this analysis, what is the most successful technique in the companys marketing mix? How much will $1 increase in expenditures for this technique affect sales?

2. How strong is the relationship between the variables? What is the explanatory power of the model? How can you interpret this?