xhibit 15-2 A regression model between sales (y in $1,000), unit price (x1 in dollars) and television advertisement (x2 in dollars) resulted in the following function: = 7 - 3x1 + 5x2 For this model SSR = 3500, SSE = 1500, and the sample size is 18. Refer to Exhibit 15-2. The coefficient of x2 indicates that if television advertising is increased by $1 (holding the unit price constant), sales are expected to increase by $5 increase by $12,000 increase by $5,000 decrease by $2,000