A shoe store developed the following estimated regression equation relating sales to Inventory investment and advertising expenditures, 9 = 29 + 10x, + 6x2 where Inventory investment ($1,0005) *= = advertising expenditures ($1,0009) you sales ($1,000s). (a) Predict the sales (in dollars) resulting from a $15,000 investment In Inventory and an advertising budget of $11,000 (b) Interpret b, and by 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