a. When considering 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?

b. When considering time series data with interest, please explain clearly how would you adjust the forecasting model to improve the forecasting accuracy? When applying 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 (Explain how to include interest rate in regression analysis using Excel TREND function).

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