Depending upon the nature of data, a time series can be classified into two types viz:
- Time series of periodical data, and
- Time series of momentary data
When the data relate to different periods of chronological order, say the profits of a concern during 2000-07, the time series constructed with such data is called a time series of periodical data. On the other hand, when the data relate to different points of time, say the total of assets of a concern on 31st December of the last 10 years, the time series constructed with such data is called a time series of momentary data.