Chapter 2 A bit of statistics
Before we move to the dicussion of ETS, ARIMA and ADAM, it makes sense to discuss some of the basics statistical terms and what they mean in the context of forecasting. Although, many of them originate from statistics and econometrics, we need to look at them from a different perspective: we are more interested in the forecasting process rather than in the estimation of parameters. Still, if you do not know statistics and econometrics well and want to have a good source on the topic, I would recommend reading an online book by Hanck et al. (2020).
Hanck, Christoph, Martin Arnold, Alexander Gerber, and Martin Schmelzer. 2020. “Introduction to Econometrics with R.” Bookdown. https://www.econometrics-with-r.org/index.html.