A time series is a sequence of values with timestamps. Some examples are daily closing stock prices, daily high temperatures at a given location, monthly U.S. job-creation numbers, quarterly earnings for a given company and more. Tweets are natural for time-series analysis because they’re time stamped. In the “Machine Learning” chapter, we’ll use a technique called simple linear regression to make predictions with time series. We’ll take another look at time series in the “Deep Learning” chapter when we study recurrent neural networks.