4 different approaches for Time Series Analysis

The first three approaches exploit differencing to make stationary the time series. Firstly, I import the dataset related to tourists arrivals to Italy from 1990 to 2019 and convert it into a time series. Data are extracted from the European Statistics: Annual Data on Tourism Industries. I use the matplotlib library. Usually, when performing time series analysis, a time series is not split into training and test set, because all the time series is needed to get a good forecast. However, in this tutorial, I split the time series into two parts -- training and test -- in order to test the performance of the tested models.