You have 4 red jelly beans and 4 green jelly beans in a paper bag. Without looking, you will pick jelly beans, one at a time, from the bag and stop when you have a green jelly bean.

Define a random variable X as the number of beans removed until you first obtain a green bean.
(a) Calculate the (probability mass function), p(x) = P (X = x), of X .

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Okay so here's my approach. I figure this is a binomial distribution with p(green) = 1/2

So would I go ahead and calculate the binomial probabilities for X = 0,1,2,3,4?