Advertising and sales. A local dairy product company in Canada wants to know the correlation between the amount of money it spent on advertising (Internet, TV, radio) and its sales (in millions of C$). They found the following regression equation.

Sales = 150 + 6.75 TV + 2.5 Radio + 2.3 Internet One of the following interpretations is correct. Which is it?

Explain what’s wrong with the others.

a) Every million dollars spent on TV advertising increases sales by C$6.75 million, after allowing for the effects of other kinds of advertising.

b) If the company did no advertising at all, then its income would be C$150 million.

c) Every million dollars spent on Internet advertising increases sales by C$2.3 million.

d) Every million dollars spent on radio advertising increases sales by C$2.5 million.