Question 15 (5 points) A regression model between sales (y in $1000s), unit price (x1 in dollars) and television advertisement (x2 in dollars) resulted in the following function: == 7 + 2x1 - 4X2 For this model, SSR = 3500, SSE - 1500, and the sample size is 18. The coefficient of the unit price indicates that if the unit price is a) increased by $1 (holding advertising constant), sales are expected to increase by $2000 b) increased by $1 (holding advertising constant), sales are expected to increase by $5000 c) decreased by $1 (holding advertising constant), sales are expected to decrease by $2000 d) increased by $1 (holding advertising constant), sales are expected to decrease by $4000 Question 18 (5 points) Exhibit 3. In a regression model involving 24 observations, the following estimated regression equation was obtained: = 29+ 18x1 +43x2 +87x3 For this model, SSR = 300 and SSE = 200. Refer to Exhibit 3. The coefficient of determination for the above model is a) .33 b) .25 Oc).75 O d) .60