Let x be a random variable that represents white blood cell count per cubic milliliter of whole blood. Assume that x has a distribut that is approximately normal, with mean = 7,600 and estimated standard deviation = 1,700. A test result of x < 3,500 is an indication of leukopenia. This indicates bone marrow depression that may be the result of a viral infection. USE SALT (a) What is the probability that, on a single test, x is less than 3,500? (Round your answer to four decimal places.) 0.0082 (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 x=7600 and = 850. The probability distribution of x is not normal. The probability distribution of x is approximately normal with x = 7600 and = 1700. The probability distribution of x is approximately normal with Mx = 7600 and 1202.0815. What is the probability of x < 3,500? (Round your answer to four decimal places.) 0.00794 (c) Repeat part (b) for n = 3 tests taken a week apart. (Round your answer to four decimal places.)