A shoe store developed the following estimated regression equation relating sales to inventory investment and advertising expenditures.

=21+12x₁+8x₂

where

x₁=inventory investment ($1,000s)x₂=advertising expenditures ($1,000s)y=sales ($1,000s).

(a)

Predict the sales (in dollars) resulting from a $14,000investment in inventory and an advertising budget of $10,000.

$

(b)

Interpretb₁andb₂

in this estimated regression equation.

Sales can be expected to increase by $for every dollar increase in inventory investment when advertising expenditure is held constant. Sales can be expected to increase by$for every dollar increase in advertising expenditure when inventory investment is held constant.