Briers, the maker of premium ice creams, conducted a regression analysis to study the factors that drive ice cream sales. The data covers monthly observations for 40 months, including the following: sales (in million units), the number of ice cream flavors, whether it is summer, and average price ($ per pound). The corresponding variables are SALES, NUMFLAVOR, SUMMER (dummy variable, =1 if the month is in summer, =0 if the month is not in summer), PRICE. The regression output is as follows:

Based on the regression output above, answer the following questions:

(1)Write the estimated regression equation.

(2)Is the overall model fit sufficiently good? Why or why not?

(3)What are the significant variables that explain monthly ice cream sales?

(4)For the coming summer, Briers has a marketing plan to sell 12 ice cream flavors at an average price of $8.00 per pound. What would be the forecast of monthly sales? Show how you derived the result.