Introduction to temporal data

In Chapter 2, we briefly introduced temporal data or data in the form of a time series or a group of time series. Time series data tracks important metrics in many different industries: daily store sales volumes, weekly software product marketing lead volumes, daily incidence of an emerging disease, yearly behavior rates (such as smoking or vegetable consumption) in a population, or hourly stock prices tracking market trends. Many related factors can influence trends over time, and some models consider these factors directly if they are known in advance.

However, consider the case of sales trends for a new gem store in a city where gem stores are a new phenomenon, perhaps somewhere rural between Haifa and Tel Aviv (Figure 6.1). Thus, there is very little known about what might influence sales. Understanding what trends exist in the time series data is critical when mining for factors that might influence sales. However, time series datasets pose significant...