More Predictive Analytics: Microsoft Excel

2. Diagnosing Trend and Seasonality

In This Chapter

Inside the Autocorrelation

Testing for Trend in the Observations

Testing for Seasonality in a Time Series

Much of the work that’s done in the smoothing approaches to predictive analytics has nothing to do with the techniques that we generally term statistical inference. If you’ve taken an introductory-to-intermediate-level course in statistics, you’ve read about those techniques. They include analyses such as confidence intervals, t-tests and the analysis of variance, multiple regression analysis, and so on.

For various reasons, there’s not much use for that sort of inferential technique in the smoothing methods. Statistical inference is useful in some smoothing situations, and this chapter ...