I was told the following:

A presumption is something you think is true before you know any facts about the matter.
An assumption is something you think is true when you miss information, but you think you have it.
The difference can be subtle. When you have certain set ideas about some things, they are also presumptions.
Women can not drive cars is a presumption.
Based on the presumption, I can assume that you can not drive, because you are a woman.

Is this right, or is there more to it?