Regression analysis was applied between demand for a product (Y) and the advertising cost of the product (X), and the following estimated regression equation was obtained. Y = 120 + 10 X Based on the above estimated regression equation: if advertising is increased by $1, then demand is expected to decrease by 10 units if advertising is increased by $1, then demand is expected to increase by 10 units if advertising is increased by $1, then demand is expected to increase by 100 units if advertising is increased by $1, then demand is expected to increase by 120 units