(1) Forecasting models use historical time series data to predict future trends and patterns. Quantitative forecasting methods are most relevant for this course. (2) Key components of time series include trends, cyclical patterns, seasonality, and irregular fluctuations. Trend lines show gradual shifts, while cyclical components involve recurring patterns above and below trends. (3) Common smoothing methods like moving averages, weighted averages, and exponential smoothing filter out irregular fluctuations to forecast stable time series without strong cycles. These methods are less effective for series with seasonal or cyclical components.