6. A linear trend equation for sales of the form Q, = at bt was estimated for the period 1999-2013 (i.e., t = 1999, 2000, . .. , 2013). The results of the regression are as follows: DEPENDENT VARIABLE: QT R - SQUARE F - RATIO P - VALUE ON F OBSERVATIONS : 15 0 . 6602 25.262 0 . 0002 PARAMETER STANDARD VARIABLE ESTIMATE ERROR T - RATIO P - VALUE INTERCEPT 73. 71460 34 . 08 2. 16 0. 0498 T 3. 7621 0. 7490 5 . 02 0. 0002 CHAPTER 7 Demand Estimation and Forecasting 271 a. Evaluate the statistical significance of the estimated coefficients. (Use 5 percent for the significance level.) Does this estimation indicate a significant trend? b. Using this equation, forecast sales in 2014 and 2015. c. Comment on the precision of these two forecasts. Consider a firm ~..1