1. Automobile unit sales at B.J. Scott Motors, Inc., provided the following 10-year time series. Year Sales Year Sales H 400 6 260 2 390 7 300 3 320 320 4 340 9 340 5 270 10 370 a. Construct a time series plot. Comment on the appropriateness of a linear trend. b. Using Minitab's procedure Stat > Time Series > Trend analysis, develop a quadratic trend equation that can be used to forecast sales and forecast sales in year 11. c. Set up the same analysis as a proper regression model. (Prepare proper variables to estimate a quadratic model and make sure to request computation of the Durbin-Watson statistic --- under "Results.." and obtain residual plots.) d. Is the model statistically significant? (Use o = 0.05) e. Obtain a point forecast and a 95% forecast interval for sales in year 11. f. Assess the assumptions about the residuals in the model of part c).Year Sales 400 390 320 340 270 260 300 320 340 10 370