Problem 1 GHM Company is a well-known automotive company in the United States. GHM has tracked the monthly sales of their main product. Ranger, over the past three years. GHM believes that there is an effect of seasons in their sales. Following are the results of CMA analysis of the monthly sales: Quarter Quarter4 0.8565 1 0558 0.8912 1. 1402 0.6076 a. Complete the table and calculate the Seasonal Index for all quarters. b. What is the interpretation of the seasonal index value? Problem 2 The following ratio-to-moving averages for the seasonally adjusted series were found by the decomposition method applied on a time series representing quarterly sales for January 2018 to December 2020 period: Ratio-to-Moving Averages yt/Et a. Calculate the Seasonal Index for every quarter. b. If the trend is described by the trend line T: = 1,000 + 30 1', What is the forecast for the fourth quarter of 2021 ? Problem 3 Siena Ltd attempts to find the trend of its sales over the past five years. Siena is considering which model that best represent the trends of its sales. Following are the result of linear and exponential model trend analysis: Variable Linear Trend Exponential Trend Intercept 0.2751 1.0426* (0.68) (0.00) t 0.85751 * 0.0979* (0.00) (0.00) Se 1.4282 0.0767 Notes: Parameter estimates are in the top part of the table with the p- values in parentheses; * represents significance at the 5 percent level; Se is used in the forecast for the exponential trend. Linear trend T yt et = yt - It letl 1 3.01 1.13 1.88 3.52 1.88 2 3.13 1.99 1.14 1.30 1.14 . . . 19 18.07 16.57 1.50 2.26 1.50 20 19.99 17.43 2.56 6.58 2.56 Total 36.72 22.06 Exponential trend T et ef let 1 3.01 3.137 -0.127 0.016 0.127 2 3.13 3.460 -0.330 0.109 0.330 . . 19 18.07 18.276 0.206 0.042 0.206 20 19.99 20.155 -0.165 0.027 0.165 Total 5.077 8.315 a) Calculate the MSE and MAD for the linear trend model b) Calculate the MSE and MAD for the exponential trend model c) Which model that performs better