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Operation Management_Forecasting

Operation Management_Forecasting

Q Forecasting Problem Greenfield’s Tannery Greenfield’s Tannery supplies leather to the South Fork Boot Company on a monthly basis for manufacturing western style boots. South Fork does not keep a large stock of inventory on hand, thus the tannery must provide sufficient leather to meet demand on a timely basis. Furthermore, the quality of the leather must be of the highest grade. The demand for western boots is lowest in the late winter, increases during the summer and fall and reaches its peak during the holiday season. The demand for leather follows the same general pattern. Greenfield’s Tannery has experienced the following monthly demand for the past fourteen months. Table 1: Data for Greenfield Tannery Problem Month Demand (in square yards) January 1300 February 1100 March 900 April 1600 May 1500 June 2100 July 2400 August 2000 September 2900 October 3200 November 3700 December 2400 January 1600 February 1000 Answer Questions 1 – 5 below. [Be sure to watch the video on how to complete your forecasting problem, in the content module.] Everything must be typed including the graph. You can complete everything in Excel if you wish. For the narrative answers, you can include these in empty cells. If you know how to add an extra worksheet, you can add your answers on a new worksheet. Please include your name somewhere. 1. Calculate a forecast of the above demand using a three and five period moving average in a table. 2. In this table, include a column for computing the forecast errors for each of the moving average forecasts. Be sure to include the cumulative forecast error for each. You can find help with this in the instructor video in Content for the week. 3. Plot these forecasts and the original data on graph paper or spreadsheet. Use a key to distinguish among your three lines. 4. Describe the results of your two forecast lines. What do they tell you? Don’t just say that one line is higher or lower than the other. Describe what’s happening with each of them compared to demand. 5. Which one would you use as a purchasing manager of Greenfield’s? Hint: Use the answer to your cumulative forecast errors to substantiate your choice. Also, make sure you include some rationale about why you are picking the method you do for this particular business, given its demand seasonality. So for example, does picking one method over the other have any impact on how much inventory they will have on hand to meet customer demand? What happens when the demand drops? Which method better supports that? Incorporating these things into your answer can earn you more points than saying that the shorter or longer one moves more slowly or quickly with demand. That is not a sufficient answer.

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From the plotted line, it is clear that the forecasting values are less than the actual demand value. Among the two forecasting values, it can be concluded that the 3-quarters moving average is a better forecasting method than the 5-quarters moving average. It is clear from the graph as the vertical distance between the demand curve and the 3-quarters forecast line is smaller than the vertical distance between the demand curve and the 5-quarters forecast line. For an example, for the 10th Quarter, the actual demand is 3200, the 3-quarters forecast is 2433.3 and the 5-quarter forecast is 2180.