Spreadsheet Implementation On Calculate Seasonal Adjustment and Exponential Smoothing

Do a forecasting through multiplicative seasonal adjustment and linear exponential smoothing of

Ý(t) = 2Y(t-1) - Y(t-2) - 2(1- a)e(t-1) + ((1- a)2)e(t-2)

Steps :

First the data must be adjusted seasonally;

Do a forecast through seasonally data via linear exponential smoothing;

• "reseasonalize" the seasonally adjusted forecasts to have output of forecasts from original series.

Picture Ilustration Of Input & Output

Here are The Step On Spreadsheet

Seasonal adjustment: on the first 6 column

Linear exponential smoothing

calculate a ( smoothing constant)

For easy, make a range name with Alpha using command: Insert/Name/Create


Significant Degree: 1 - a

Mean square error: MSE= VAR (errors)+ (AVG(errors))2.

Confident interval: Ci : Forecast ± RMSE

Download File : http://thexdata.com/index.php?option=com_docman&task=doc_download&gid=1&&Itemid=26



March 29, 2008 at 11:42 AM

linkna dah dipasang thx ya dah mampir :D