Notes on Time Series Analysis, ARIMA Models and Signal Extraction.

Present practice in applied time series work, mostly at economic policy or data producing agencies, relies heavily on using moving average filters to estimate unobserved components in time series, such as the seasonally adjusted series, the trend, or the cycle. The purpose of the present paper is to provide an informal intordution to the time series analysis tools and concepts required by the user or analyst to understand the basic methodology behind the application of filters.