British Airways share trading volumes
Use this diagram to explain the idea of forecasting one value from the previous value. (This time series has minimal long-term trend, so it does not need to be detrended first.)
The line on the scatterplot is used to do the forecasting. It can be dragged into any position, but two are particularly meaningful:
Click any cross on the time series plot at the top to illustrate the forecast.
The data set shows the volume of British Airways shares (millions) traded in the first 57 trading days of 2002 — between 2nd January and 21st March.