33:799:310 Lecture 8: time series I
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Holt"s exponential smoothing (project 2: winter"s exponential smoothing (project 2, exam 2) See microsoft excel 2010: data analysis and business. Uses the average of all the historical data as the forecast. When new data becomes available , the forecast for time t+2 is the new mean including the previously observed data plus this new observation. This method is appropriate when there is no predictable trend or seasonality. Moving averages: a moving average of order k, ma(k) is the value of k consecutive observations. K is the number of terms in the moving average: the moving average model does not handle trend or seasonality very well although it can do better than the total mean. Moving averages: picking the right k is very tricky, noises may be meaningful cycles. Period (t) sales (y: the weekly sales figures (in millions of dollars) presented in the following table are used by a major department store to determine the need for temporary sales personnel.
