Ex1-Quantitative Methods

1. The Instant Paper Clip Office Supply Company sells and delivers office supplies to companies, schools, and agencies within a 50mile radius of its warehouse. The office supply business is competitive, and the ability to deliver orders promptly is a big factor in getting new customers and maintaining old ones. (Offices typically order not when they run low on supplies, but when they completely run out. As a result, they need their orders immediately.) The manager of the company wants to be certain that enough drivers and vehicles are available to deliver orders promptly and that they have adequate inventory in stock. Therefore, the manager wants to be able to forecast the demand for deliveries during the next month. From the records of previous orders, management has accumulated the following data for the past 10 months:  Compute the monthly demand forecast for April through November using a 3-month moving average.  Compute the monthly demand forecast for June through November using a 5-month moving average.  Compute the monthly demand forecast for April through November using a 3-month weighted moving average. Use weights of 0.5, 0.33, and 0.17, with the heavier weights on the more recent months.  Which one is better? Why?  Is there tendency? Why? Date Quarter Data Dec-83 Mar-84 Jun-84 Sep-84 Dec-84 Mar-85 Jun-85 Sep-85 Dec-85 Mar-86 Jun-86 Sep-86 Dec-86 Mar-87 Jun-87 Sep-87 Dec-87 Mar-88 Jun-88 Sep-88 Dec-88 Mar-89 Jun-89 Sep-89 Dec-89 Mar-90 Jun-90 Sep-90 Dec-90 Mar-91 Jun-91 Sep-91 Dec-91 Mar-92 Jun-92 Sep-92 Dec-92 Mar-93 Jun-93 Sep-93 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 147.6 251.8 273.1 249.1 139.3 221.2 260.2 259.5 140.5 245.5 298.8 287 168.8 322.6 393.5 404.3 259.7 401.1 464.6 479.7 264.4 402.6 411.3 385.9 232.7 309.2 310.7 293 205.1 234.4 285.4 258.7 193.2 263.7 292.5 315.2 178.3 274.5 295.4 311.8 2. Using data shown, identify the following:   Tendency Seasonality Compute the quarterly forecast (h=8) with the following methods:   Classic decomposition Holt-Winters´ Which one is better? Why?