DECILE |
Deciles are used to give an element a ranking. For example, a decile rainfall
map will show whether the rainfall is above average, average or below average
for the time period and area you have already chosen.
How to calculate deciles
If, for example, you had 40 years of annual rainfall records, you would
first need to arrange the totals in ascending order (from lowest to highest).
Next split them into 10 equal groups, so that in this example there would
be 10 groups of four. The first group (four lowest annual rainfalls on
record) would be in decile range one, the second group in decile range
two, up to the four highest annual totals (highest 10 per cent) being
in decile range 10.
If you choose amounts, you will see the quantity of the element requested.
For example, choosing the amounts column under Rainfall Maps will show how much
rainfall (in millimetres) has fallen for the time period and area chosen. |
