Let X∼Negative Binomial(r,p)X \sim \text{Negative Binomial}(r, p)X∼Negative Binomial(r,p) with shape r=3r = 3r=3 and success probability p=0.5p = 0.5p=0.5. What is E[X]E[X]E[X]?
333
666
1.51.51.5
Cannot determine