Microsoft Excel 2019 Data Analysis and Business Modeling, 6th Edition

Chapter 66 Ratio-to-moving-average forecast method

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 the 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 named Ratioma.xlsx, you are given the sales of a product during 20 quarters (shown later in Figure 66-1 in rows 5 through 24), and you want to predict the sales during the next four quarters (Quarters 21–24). This time ...