Well-Defined Sets: Examples & Real World Use

[Kristinanne]

Homework Statement

Describe what it means for a set to be well defined and then give an example of a well defined set and an example of a set that isn’t well defined. Explain why it is so important for sets used in the real world, for example in marketing research, to be well defined.

Homework Equations

The Attempt at a Solution

A well defined set is clear without question. I am just unsure of how to use that in real life examples. Same with the one that isn't well defined.

 

[mutton]

Maybe the set of all people currently living on Earth who like ice cream is not well-defined because there are people who neither like nor dislike it, people who like some flavours but dislike others, people who don't know what ice cream is, etc. This is a problem if you want to survey what percentage of people like ice cream, so you have to clearly specify the subset you are looking at.

You can think of better examples.