- #1
Obraz35
- 31
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Homework Statement
The probability mass function of a random variable X is:
P(X=k) = (r+k-1 C r-1)pr(1-p)k
Give an interpretation of X.
Homework Equations
The Attempt at a Solution
The PMF looks like the setup for a binomial random variable. The first combination looks like you are arranging r-1 successes in r+k-1 slots. And the pr seems like it is giving the probability of r successes occurring. But I don't see what X as a whole is standing for.