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Problem 4. A certain specification of a beam has a normally-distributed failure strength with a mean and standard deviation of 7000 psi and 1000 psi, respectievly. (a) Let X be the average failure strength from a random sample of 100 beams. What are the mean and standard deviation of X? (b) How would your answer to the previous part change if the random sample only consisted of 16 beams? (c) If the sample size is 16 beams, calculate P(6500