probability

Ryan$

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Jan 25, 2019
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Hi guys, I have a lil confusion on probability ...
how could it be a probability on something but at the end it's zero? I mean like this question
the probability of accommodating people in specific area is zero, but to find how many people on that area could be zero! I mean however there's probability but that doesn't mean actually there would be "people" on that area, might be zero ... how is that logically?! it's not making sense .. since we have probability of accommodating on specific area .. then there would be people there why not?! any help
 

tkhunny

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You're right. It makes no sense at all as you have presented it.

Things that are not possible should not even be in the universe.
 

Ryan$

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but if it's not possible then how it has probability?! I mean we could have probability but in total we have zero .. ?!
 

tkhunny

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but if it's not possible then how it has probability?! I mean we could have probability but in total we have zero .. ?!
I think you did nor understand my second comment.

If it isn't possible, the probability is zero and it should not be included in your distribution.

Example:

1) What is the universe of possibilities resulting from you sneezing?

2) What is the probability of a cow jumping over the moon because it is frightened by your sneeze?

3) You didn't include cows jumping over the moon in your first answer, did you?
 

Ryan$

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No you didn't understand me ! :)
lets assume this example: the probability of people in area x is 1/2 but "sometimes" when we want to calculate how many people on that area then we would get "zero" people ! however the probability of getting people to that area is 1/2 ..so how is that logically ..the physical amount of people in that area is zero however the probability to get one of the people on that area is 1/2 ? doesn't that mean if I have probability then ofcourse I would get amount on what probability denote ?! something new to me
 

topsquark

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No you didn't understand me ! :)
lets assume this example: the probability of people in area x is 1/2 but "sometimes" when we want to calculate how many people on that area then we would get "zero" people ! however the probability of getting people to that area is 1/2 ..so how is that logically ..the physical amount of people in that area is zero however the probability to get one of the people on that area is 1/2 ? doesn't that mean if I have probability then ofcourse I would get amount on what probability denote ?! something new to me
I see what you are saying but it would be best if you could give an actual problem as an example rather than explaining what's wrong with it. For example, in Quantum Mechanics a "plane wave" can be a solution to the Schrodinger equation but the probability of a particle being at any particular point is zero for this solution. There's a way to explain this one (the Heisenberg Uncertainty Principle) so it is possible to do (but very arcane as far as the Mathematics are concerned.) It may be that there is a way to explain how it could happen but we can't say that until a specific question is raised.

-Dan
 

tkhunny

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* One Person
* Two Rooms
* The individual moves from one room to the other on whatever schedule allows us to assume that...
* The probability of being in either room is 1/2.

If the person is found in one room, are you truly disturbed that he/she is not in the other room?

You need a complete probability distribution. If you talk about only half of it, it never will make any sense.
 
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