Let x be a random variable that represents white blood cellcount per cubic milliliter of whole blood. Assume that x has adistribution that is approximately normal, with mean ? = 6950 andestimated standard deviation ? = 2650. A test result of x < 3500is an indication of leukopenia. This indicates bone marrowdepression that may be the result of a viral infection. (a) What isthe probability that, on a single test, x is less than 3500? (Roundyour answer to four decimal places.) (b) Suppose a doctor uses theaverage x for two tests taken about a week apart. What can we sayabout the probability distribution of x? The probabilitydistribution of x is not normal. The probability distribution of xis approximately normal with ?x = 6950 and ?x = 1873.83. Theprobability distribution of x is approximately normal with ?x =6950 and ?x = 1325.00. The probability distribution of x isapproximately normal with ?x = 6950 and ?x = 2650. What is theprobability of x < 3500? (Round your answer to four decimalplaces.) (c) Repeat part (b) for n = 3 tests taken a week apart.(Round your answer to four decimal places.) (d) Compare youranswers to parts (a), (b), and (c). How did the probabilitieschange as n increased? The probabilities decreased as n increased.The probabilities stayed the same as n increased. The probabilitiesincreased as n increased. If a person had x < 3500 based onthree 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 testsbelow 3,500 purely by chance. The person probably does not haveleukopenia. It would be a common event for a person to have two orthree tests below 3,500 purely by chance. The person probably hasleukopenia. It would be an extremely rare event for a person tohave two or three tests below 3,500 purely by chance. The personprobably has leukopenia. It would be an extremely rare event for aperson to have two or three tests below 3,500 purely by chance. Theperson probably does not have leukopenia.