1. ## Re: Discrete Random Variable

Any ideas guys, this homework assignment is due tonight and need to submit it soon

2. ## Re: Discrete Random Variable

So I am still trying to provide hints so that you can apply the method mentioned by Dason at #8 (as you claim you understand that)

Maybe another question: Can you show that the sum of the pmf of a Geometric distribution equals to 1?

3. ## Re: Discrete Random Variable

I understand that all the vals must add up to 1 but when i take the formula i get the following:
s=1((1-3^n)/(1-3))
-2s=1-3^n
S=(1-3^n)/2

where s=c BUT that doesnt give me a value because n is still unknown, i dont know why im having this much trouble with this problem heh.

4. ## Re: Discrete Random Variable

n isn't unknown. Read your problem again. You have a finite number of terms that you're summing over.

5. ## Re: Discrete Random Variable

Also note that r isn't 3. You're pdf is of the form f(X=x) = c/x so you want to sum 1 + 1/3 + 1/3^2 + ... 1/3^m

6. ## Re: Discrete Random Variable

so n = 1 ?

This is where im confused.

7. ## Re: Discrete Random Variable

Got it figured out thanks.