Questions answered in this chapter:
What is the trend of a time series?
How do I define seasonal indexes for a time series?
Is there an easy way to incorporate trend and seasonality into forecasting future product sales?
Often you need a simple, accurate method to predict future quarterly revenues of a corporation or future monthly sales of a product. The ratio-to-moving-average method provides an accurate, easy-to-use forecasting method for these situations.
In the file Ratioma.xlsx, you are given sales of a product during 20 quarters (shown later in Figure 60-1 in rows 5 through 24), and you want to predict sales during the next four quarters (quarters 21-24). This time series has both trend and ...