Time Series

secular trend

• the long term and overall direction of the data

• positive or negative trend

cycle

• patterns of peaks and low in data that occur over intervals greater than year

• they are periodic movements in time series

period

• the time taken for 1 complete cycle

seasonality

• periodic patterns in data that occur regularly throughout the calendar year

• have a fixed and known time period

• e.g. fruit picking season

structural change

• sudden change in the established pattern in data

  

outliers

individual values that stand out from the general body of data

irregular (random) fluctuations

• variation in data that can’t be attributed to systematic changes like trend, cycle, seasonality, structural changes or outliers

  

time series

• data collected over time

• it is analyses to identify patterns in data, make predictions and draw conclusions

variables in time series

• time is the independent variable

• look at how data changes depending on time

trend, cycle and seasonality