Forecasts of rainfall in Moorings (Monze), Zambia
The horizontal positions of the crosses are the actual rainfalls in October to December each year. The cross for each year appears in the top jittered dot plot (all years) and also
The rainfall was forecast earlier in each year to be High, Average or Low and this is the vertical grouping in the diagram.
Use the diagram to explain that if the forecast is good, the spread of actual rainfalls for each forecast group is lower than the overall spread.
Mention that a good forecast explains some of the overall variability. Use the slider to compare good and bad forecasts.
The most important planting time in Southern Zambia is October-December, and availability of good rainfall forecasts for that period would help farmers to decide which crops to plant and when the planting should take place.
The data set contains the rainfall totals for October-December at Moorings (Monze), Zambia for the years 1922 to 2003.