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[數學] 有關統計學問題 (10點)

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Refer to the following table which contains the sales (in $, 000) for a department store for the first ten months for the year. Month SalesJanuary 440February 480March 590April 400May 500June 550July 470August ... 顯示更多 Refer to the following table which contains the sales (in $, 000) for a department store for the first ten months for the year. Month Sales January 440 February 480 March 590 April 400 May 500 June 550 July 470 August 500 September 600 October 520 1) Using a three period moving average (i.e. MA(3)) as a forecasting method, what is the MAPE for this forecasting model _____%. 2) Using simple exponential smoothing (with a smoothing constant of 0.2) as a forecasting method, what is the MSE for this forecast model? 各位數學高手, 請幫幫忙吧, 謝謝!

最佳解答:

Using three period moving average Time Value Perdict Error/Actual 1 440 2 480 3 590 4 400 503.3333 0.258333333 5 500 490 0.02 6 550 496.6667 0.096969697 7 470 483.3333 0.028368794 8 500 506.6667 0.013333333 9 600 506.6667 0.155555556 10 520 523.3333 0.006410256 The MAPE for this forecasting model 5.7897 % Using simple exponential smoothing (with a smoothing constant of 0.2) Time Value Perdict Error ERROR-SQUARE 1 440 440 0 0 2 480 440 40 1600 3 590 448 142 20164 4 400 476.4 76.4 5836.96 5 500 461.12 38.88 1511.6544 6 550 468.896 81.104 6577.858816 7 470 485.1168 15.1168 228.5176422 8 500 482.0934 17.90656 320.644891 9 600 485.6748 114.3252 13070.26233 10 520 508.5398 11.4602 131.3361474 The MSE for this forecast model is 70.3145 I have make the assumption that the forecasting value of January is equal to its actual value.

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