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= 6350 and estimated standard deviation σ= 2650. 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.) 1 (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? The probability distribution of x is approximately normal with μx = 6350 and σx = 2650.The probability distribution of x is approximately normal with μx = 6350 and σx = 1873.83.The probability distribution of x is approximately normal with μx = 6350 and σx = 1325.00.The probability distribution of x is not normal. What is the probability of x< 3500? (Round your answer to four decimal places.) 3 (c) Repeat part (b) for n = 3 tests taken a week apart. (Round your answer to four decimal places.) 4 (d) Compare your answers to parts (a), (b), and (c). How did the probabilities change as n increased? The probabilities decreased as n increased.The probabilities stayed the same as n increased.The probabilities increased as n increased. If a person had x< 3500 based on three tests, what conclusion would you draw as a doctor or a nurse? 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.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.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.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. Use the Student's t distribution to find tc for a 0.95 confidence level when the sample is 22. (Round your answer to three decimal places.)