Time series plots, trend, seasonality and irregular fluctuation; moving averages, seasonal indices, deseasonalising and trend-line forecasting

What this note covers

1. Read the structure of a time series
2. Smooth short-term variation with moving averages
3. Calculate seasonal indices from cycles
4. Deseasonalise observations and fit trend
5. Forecast and restore seasonality
6. Communicate a complete time-series analysis

6 sections · 10 key terms & formulas · 6 common mistakes