For each given situation, determine/indicate the probability distribution model that fits the random variable being described.

9. . Suppose that the average number of telephone calls arnving at the switch board of a small corporation is 30 calls per hour. Let the random variable X be the number of calls that will arrive within a 5minute interval- Sumsang Mobile Inc. has an acceptance scheme before purchasing a lot containing large number of phone batteries. From a lot containing 200 phone batten'es (8 of them are nonconforming), a sample of ten batteries (without replacement] is tested for nonconformity- Let 1the random variable X be the number of nonconforming phone batten'es in the sample- The sum of independently and identicallyr disln'buted Geometric random vanables- Consider the activity of selecting at random newly manufactured light bulbs and observing whether the bulb is defective or not. Let the random variable X be the number of light bulbs observed until the 3rd defective bulb is detected. A random van'able that follows a special case of the Gamma distribution that x 1 21 '3 Ham-II '9 has parameters a = Eand B = 2 (Le. Gamma[a,) where fJr = The sum of independently distn'buted Binomial random variables that have a common parameter, p. The sum of independent random variables that are Nonnally disbibuted. _ 2 A random variable U, dened as U = (n 61:5 , where 5'2 is the sample variance of a random sample from a Normal distn'bution with mean p: and variance 02- The square of a random variable that follows a Student's t distn'bution. 1U.The sum of independent Chiquare van'ables