2. If the discrete RV X can take the values 0, 1, 2, ..., k, such that ed . at P(X = i) : i! i = 0, 1, 2, ..., k, then X is said to follow a Poisson distribution with parameters 1. 3. If the discrete RV X can take the values 0, 1, 2, ..., such that P(X = i) = nti-C;p" q', i = 0, 1, 2, ..., where p + q = 1, then X is said to follow a Pascal(or negative binomial) distribution with parameters n. 4. A Pascal distribution with parameter n = 1i.e., P(X = i) = 1ti-C;plq' = Cpq' = pq', i= 0, 1,2, ... , where p + q = 1, is called a Geometric distribution