Meeting with eng Nedaa and the 1st step in working

On Thursday (20-8-209),
We met eng.Nedaa and she told us to begin with testing different techniques of forecasting on the data we have and find the best technique by any of the different measures like [MAPE] .
=>We are now working on a sample [all the countries over 3 sectors only as a beginning]and applying five methods:
1-the Moving average of order 3
2-single exponential Smoothing,
3-double exponential [Holt Linear],
4-Triple Exponential [Holt Winter]
5-regression Forecasting.
=>We selected the MAPE as our accuracy measure
=>We are facing a problem that the Holt winter and holt linear Methods don't have the same equations in all references
and this results in different solutions and we can't determine which equation is the correct one.
=>We determined to use the XLMiner AddIn in the Excel to be sure of its results about these two methods.