GardenBanter.co.uk - View Single Post - Hi im new :-) and fairly new to gardening :-S

25-01-2011, 01:02 PM posted to uk.rec.gardening

wrote:
The area in circle A but not in B represents the elements that
have propert A but not property B, and the area in the overlap
represents the ones that have both properties. And so on.
A bit like a Vector, a mathematical model to prove or disprove a theory?
Yes and no. They are used to demonstrate properties, rather than
prove them. They are more like graphs (in the school sense).

In more practical terms, I think they're used to demonstrate demographics,
etc, for advertising + management types