Test i state whether each of the following sets is well...

Test I. State whether each of the following sets is WELL-DEFINED or NOT. ___________ 1. The set of happy people ___________ 2. The set of enjoyable subjects in high school ___________ 3. The set of good teachers ___________ 4. The set of even counting numbers ___________ 5. The set of prime numbers ___________ 6. The set of all factors of 24 ___________ 7. The set of big people ___________ 8. The set of all even numbers from 2 to 10 ___________ 9. The set of hardworking frontline workers ___________ 10. The set of responsible citizens.

Transcript

00:03 Okay, we're looking for well -defined sets.

00:10 Well, is that not a hyphen in it? well -defined sets.

00:29 Okay, so a well -defined set is a set where there's agreement over what belongs in the set and what doesn't belong in the set.

00:47 So when we see words like happy, well, how do you define who's happy and who's not? one person might say, this person's happy, and another person might say, no, they're not exactly happy enough for me to put them in my set of happy people.

01:10 So two different people making these sets might disagree on what the members of the set are.

01:21 So this one's a great example of one that is not well -defined.

01:28 The set of enjoyable subjects.

01:31 Well, again, we can disagree on what's enjoyable.

01:39 The set of good teachers.

01:41 Can we disagree on what a good teacher is? sure, we can disagree.

01:53 The set of even counting numbers.

01:56 Well, it's two, four, six, eight, 10, 12.

02:01 Could a reasonable person disagree with me on that? someone could say, hey, i thought three was an even counting number.

02:09 Well, they're incorrect.

02:12 So there's no possible disagreement here by reasonable people.

02:18 So this one here is a well -defined set.