Refer again to the gasoline sales time series data in the following table. Using
ID: 375979 • Letter: R
Question
Refer again to the gasoline sales time series data in the following table.
Using a weight of 1/2 for the most recent observation, 1/3 for the second most recent, and 1/6 for third most recent, compute a three-week weighted moving average for the time series. Use rounded for two decimal places values for intermediate colculations.
Compute the MSE for the weighted moving average in part a. Do you prefer this weighted moving average to the unweighted moving average? Remember that the MSE for the unweighted moving average is 10.22. Round your answer to two decimal places.
MSE = ?
Prefer the ??? moving average here.
Suppose you are allowed to choose any weights as long as they sum to 1. Could you always find a set of weights that would make the MSE smaller for a weighted moving average than for an unweighted moving average? Why or why not?
Week Sales (1000s of gallons) 1 18 2 22 3 19 4 24 5 19 6 17 7 22 8 19 9 25 10 20 11 14 12 24Explanation / Answer
Weighted average wil lstart from Week 4 which will be = 1/2*19 + 1/3*22 + 1/6*18 = 19.83
MSE = SUM of Error Square/(Total number of forecasted value - 1) = 179.50/(9-1) = 22.44
Will prefer the unweighted moving average due to lower MSE
Yes, we should always aim to have lowest possible MSE as it shows the accurancy of forecast. More the MSE means higher are the deivation from actual vlaue for the forecast
Week Sales Forecast (F) Error (D-F) Error Sq 1 18 2 22 3 19 4 24 19.83 4.17 17.36 5 19 22.00 (3.00) 9.00 6 17 20.67 (3.67) 13.44 7 22 18.83 3.17 10.03 8 19 19.83 (0.83) 0.69 9 25 19.67 5.33 28.44 10 20 22.50 (2.50) 6.25 11 14 21.50 (7.50) 56.25 12 24 17.83 6.17 38.03 78 243 182.67 1.33 179.50Related Questions
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