Let x be a random variable that represents white blood cell count per cubic milliliter of whole blood. Assume that x has a distribution that is approximately normal, with mean µ = 7350 and estimated standard deviation o 2300. A test result of x < 3500 is an indication of leukopenia. This indicates bone marrow depression that may be the result of a viral infection. (a) What is the probability that, on a single test, x is less than 3500? (Round your answer to four decimal places.) (b) Suppose a doctor uses the average x for two tests taken about a week apart. What can we say about the probability distribution of x? O The probability distribution of x is not normal. O The probability distribution of x is approximately normal with u - 7350 and o, = 1626.35. O The probability distribution of x is approximately normal with u,- 7350 and o,- 1150.00. O The probability distribution of x is approximately normal with u, - 7350 and o, 2300. What is the probability of x < 3500? (Round your answer to four decimal places.) (c) Repeat part (b) for n= 3 tests taken a week apart. (Round your answer to four decimal places.) (d) Compare your answers to parts (a), (b), and (c). How did the probabilities change as n increased? O The probabilities increased as n increased. O The probabilities stayed the same as n increased. O The probabilities decreased as n increased. If a person had x < 3500 based on three tests, what conclusion would you draw as a doctor or a nurse? O It would be an extremely rare event for a person to have two or three tests below 3,500 purely by chance. The person probably has leukopenia. O It would be a common event for a person to have two or three tests below 3,500 purely by chance. The person probably has leukopenia. O It would be an extremely rare event for a person to have two or three tests below 3,500 purely by chance. The person probably does not have leukopenia. O It would be a common event for a person to have two or three tests below 3,500 purely by chance. The person probably does not have leukopenia.