Please refer to the Excel data file "Equipment Sales from 1993 to 2005", which includes the sales record from 1993 to 2005 of a large semiconductor company in US.

(a)When consider "time series data" only, please compare at least 4 different time-series forecasting methods and select the best time-series forecasting model with clear explanation of why it is better than others. For each method you compare, what are the quarterly sales to be expected in 2006? What are the differences in forecast accuracy?

Hint: This discussion is similar to Question 2(a)

(b)When consider "time series data with interest", please explain clearly how would you adjust the forecasting model to improve the forecasting accuracy? When apply the new forecasting model, what are the quarterly sales to be expected in 2006? What is the forecast accuracy as compare with other methods? Please describe your approach clearly and explain how interest rate may affect the forecasting accuracy.

Hint:

Explain how to include "interest rate" in regression analysis using Excel "TREND" function.

Explain what the forecasting results are and how the accuracy of forecasting results can be improved.

What is your observation on how interest rate may affect sales forecast?