Time Series:

Time series data are measurements of a variable taken at regular intervals over time. Time series are represented as sequences of values like x(1), x(2), ... .

A wide class of practically important data are represented as time series: economic and social data, weather records, sports data, to name a few.

Some simple examples of time series are records on monthly unemployment rates, average daily atmospheric temperature, or monthly scores of a football team.

In statistics, time series are often considered as realizations of random series .