uarterly sales totals are shown below. quarter year 1 year 2 year 3 1 57 73 89 2 79 95 111 3 52 68 84 4 61 77 93 year 4 105 127 100 109 Use multiple regression with dummy variables to develop an additive decomposition forecasting model for these data. Model the trend component using the time periods, numbered 1-16. Model the seasonality using dummy variables for quarters 1-3 (use quarter 4 as the baseline). Hints: Copy-and-paste data into Excel. Re-format the data into columns. Create a period variable and dummy variables for quarter 1, quarter 2, and quarter 3. Fill in the blanks below with the coefficients that you estimate from the data. Predicted sales = + x period + x Q1 + x Q2 + x Q3