Can you calculate probability with infinite sets?

[gamow99]

Suppose set A is defined as the even integers and set B is defined as for every even integer there are two odd integers, like so: {2,3,3,4,5,5,6,7,7 ... }

Can you calculate that the probability of choosing an odd number is 66%?

 

[Orodruin]

Not without an appropriate probability distribution.

 

[gamow99]

Don't know what you mean.

 

[Orodruin]

In order to give a probability for something to happen you need to specify the probability distribution for the possible outcomes.

 

[Zafa Pi]

Don't know what you mean.

Then you should not have used the Intermediate classification for your thread. There is no natural probabilistic method for selecting a member from a countably infinite set.
If you choose uniformly from {2,3,3',4,5,5', ... 10^20) then the probability of selecting an odd is very close to 2/3. The uniform distribution is natural for a finite set, but there is no such for the infinite case.