Union Definition: P(AB) and P(AB)c Explained

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Homework Help Overview

The discussion revolves around the concepts of probability, specifically focusing on unions and complements in set theory. Participants are seeking clarification on the notation and meaning of expressions such as P(AB) and P(AB)c, as well as related definitions involving set operations.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants are attempting to define the expressions related to probability and unions, questioning the meaning of P(AB) and its complement. There is also exploration of the implications of these definitions in the context of sets A and B.

Discussion Status

The discussion is ongoing, with participants providing insights and seeking further clarification on the definitions and implications of the probability expressions. Some guidance has been offered regarding the interpretation of complements and unions, but no consensus has been reached.

Contextual Notes

Participants are working under the constraints of a homework assignment, which may limit the depth of exploration into the concepts. There is a focus on ensuring correct definitions and understanding of the notation used in probability.

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Homework Statement



Can you guys explain to me what the following mean.

We are working on probability and unions, and these came up on the homework and need to know what these mean in order to solve the problem.

Thanks

P(AB)

P(AB)c

Where c is the compliment.

Also i want to make sure I have the following definitions correct.

P(A∪Bc)
Means all the sets not including B



Homework Equations





The Attempt at a Solution

 
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Mdhiggenz said:

Homework Statement



Can you guys explain to me what the following mean.

We are working on probability and unions, and these came up on the homework and need to know what these mean in order to solve the problem.

Thanks

P(AB)
Likely the probability of ##A\cap B##
P(AB)c

Where c is the compliment.
That's spelled complement. I would say that need another set of parentheses and I'm guessing it means the probability of ##(A\cap B)^c##
Also i want to make sure I have the following definitions correct.

P(A∪Bc)
Means all the sets not including B

It is a probability, not a set or a point. But what about a point that is in A and in B?
 
Thanks for the response, wouldn't a set in A and in B still have B in it, so be irrelevant?
 
Mdhiggenz said:
Thanks for the response, wouldn't a set in A and in B still have B in it, so be irrelevant?

It doesn't make sense to talk about "set in A and in B". A and B are sets. They have elements or members, or, informally, in the case of Venn diagrams, points in them. The notation shows the complement on B. But a point in A is in that union whether or not it is also in B.
 
so when they say B complement, it simply means calculate everything except the section that is "pure" B. Such as include the ones that are neither A or B?
 
Mdhiggenz said:
so when they say B complement, it simply means calculate everything except the section that is "pure" B. Such as include the ones that are neither A or B?

Yes, the complement of B is everything that is not in B. It, itself, has nothing to do with A.
 

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