4QA3 F12 Week 5 Lecture Notes

4QA3 F12 Week 5 Lecture Notes

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Unformatted text preview: data after N b= Example only requires last 4QA3 F12 S xx = n 2 (n + 1)(2n + 1) / 6 − [ n( n + 1) / 2]2 i S xy S xx a = D − b(n + 1) / 2 27 ●  Holt’s method is a type of double exponential smoothing to forecast time series with linear trend. Ft ,t+ τ = St + τ Gt ( )( ) ) + (1 − β ) G St = α Dt + 1 − α St -1 + Gt -1 ( Gt = β St − St -1 where t -1 Prior forecast of the current demand Previous slope forecast St : Intercept estimate for period t Gt : Slope (trend) estimate for period t α: a smoothing constant for intercept : a smoothing constant for trend 4QA3 F12 28 Period Month Demand Level St Trend Gt Forecast Ft 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 - Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar - 37 40 41 37 45 50 43 47 56 52 55 54 – - - 35 36.85 39...
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This document was uploaded on 04/01/2014.

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