• Time series decomposition seeks to separate the time series (Y) into 4 components: trend (T), cycle (C), seasonal (S), and irregular (I). What is the difference between these components?
• The model can be additive or multiplicative. When do we use an additive model? When do we use a multiplicative model?
• We have different ways of showing and projecting trends in a time series. the three most common are moving averages, exponential smoothing and our new friend, regression analysis. How might any of these be used? Have you seen any in use?