The properties of PMF for discrete random variable

[Chilissy]

Hey guys,

I've found the properties of PMF for discrete random variables, and I was wondering if my thinking is ok.

So the first property is simple, as it states, that function is pmf for all 'i' contained in Natural numbers.

But there's an infinite amount of natural numbers. My question is: Does the second property of summations means, that the function is pmf when there's a finite or countably infinite amount of naturals?

Thanks!

 

[blamocur]

Hey guys,

I've found the properties of PMF for discrete random variables, and I was wondering if my thinking is ok.

So the first property is simple, as it states, that function is pmf for all 'i' contained in Natural numbers.

But there's an infinite amount of natural numbers. My question is: Does the second property of summations means, that the function is pmf when there's a finite or countably infinite amount of naturals?

Thanks!

Not sure I understand your question, but subsets of natural numbers can only be finite or countably infinite.

 

[Steven G]

Hey guys,

I've found the properties of PMF for discrete random variables, and I was wondering if my thinking is ok.

So the first property is simple, as it states, that function is pmf for all 'i' contained in Natural numbers.

But there's an infinite amount of natural numbers. My question is: Does the second property of summations means, that the function is pmf when there's a finite or countably infinite amount of naturals?

Thanks!

When there's a finite or countably infinite amount of naturals. As I am sure that you know, there are a countably infinite number of natural numbers. What this means is that you should try and state your question the way you meant to.

Hint: I think that you meant to ask about i.

Why do you think that i should only range over a finite number of naturals?